Unum (UNM) 10-K 23 Feb 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Feb. 21, 2023	Jun. 30, 2022
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Transition Report	false
Entity File Number	001-11294
Entity Registrant Name	Unum Group
Entity Central Index Key	0000005513
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	62-1598430
Entity Address, Address Line One	1 Fountain Square
Entity Address, City or Town	Chattanooga,
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	37402
City Area Code	423
Local Phone Number	294-1011
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		197,294,182
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 6,800,000,000
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Chattanooga, Tennessee
NEW YORK STOCK EXCHANGE, INC. | Common Class A
Entity Information [Line Items]
Title of 12(b) Security	Common stock, $0.10 par value
Trading Symbol	UNM
Security Exchange Name	NYSE
NEW YORK STOCK EXCHANGE, INC. | 6.250% Junior Subordinated Notes due 2058
Entity Information [Line Items]
Title of 12(b) Security	6.250% Junior Subordinated Notes due 2058
Trading Symbol	UNMA
Security Exchange Name	NYSE

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Investments
Fixed Maturity Securities - at fair value (amortized cost of $37,825.2; $37,386.7; allowance for credit losses of $—; $—)	$ 34,840.8	$ 43,336
Mortgage Loans (net of allowance for credit losses of $9.3; $8.3)	2,435.4	2,560.4
Policy Loans	3,601.2	3,662.9
Other Long-term Investments	1,440.1	1,203
Short-term Investments	1,394.8	1,388
Total Investments	43,712.3	52,150.3
Other Assets
Cash and Bank Deposits	119.2	75
Accounts and Premiums Receivable (net of allowance for credit losses of $32.5; $34.2)	1,482.1	1,519.9
Reinsurance Recoverable (net of allowance for credit losses of $1.7; $2.3)	10,218.6	10,919.3
Accrued Investment Income	615	602.7
Deferred Acquisition Costs	2,252.3	2,207.9
Goodwill	347.6	352.2
Property and Equipment	451.7	462.7
Deferred Income Tax Assets, Net	449.8	0
Other Assets	1,786.3	1,825.6
Total Assets	61,434.9	70,115.6
Liabilities
Policy and Contract Benefits	1,839.8	1,907.7
Reserves for Future Policy and Contract Benefits	42,330.2	48,007.5
Unearned Premiums	352.7	347.5
Other Policyholders' Funds	1,750.4	1,790.9
Income Tax Payable	190.9	159.1
Deferred Income Tax	9.2	458.4
Short-term debt	2	0
Long-term Debt	3,427.8	3,442.2
Other Liabilities	2,334.4	2,585.9
Total Liabilities	52,237.4	58,699.2
Commitments and Contingent Liabilities - Note 14
Stockholders' Equity
Common Stock, $0.10 par; authorized: 725,000,000 shares; issued: 308,306,490 and 307,334,853 shares	30.8	30.7
Additional Paid-in Capital	2,441	2,408.1
Accumulated Other Comprehensive Income (Loss)	(2,756.6)	354.1
Retained Earnings	12,912.1	11,853.2
Treasury Stock - at cost:110,551,977 and 104,820,670 shares	(3,429.8)	(3,229.7)
Total Stockholders' Equity	9,197.5	11,416.4
Total Liabilities and Stockholders' Equity	$ 61,434.9	$ 70,115.6

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Investments
Amortized Cost of Fixed Maturity Securities	$ 37,825.2	$ 37,386.7
Debt Securities, Available-for-sale, Allowance for Credit Loss for Fixed Maturity Securities	0	0
Allowance for credit losses for Mortgage Loans	9.3
Other Assets
Premium Receivable, Allowance for Credit Loss	32.5	34.2
Reinsurance Recoverable, Allowance for Credit Loss	$ 1.7	$ 2.3
Stockholders' Equity
Common Stock, Par Value (in dollars per share)	$ 0.10	$ 0.10
Common Stock, Shares Authorized	725,000,000	725,000,000
Common Stock, Shares Issued	308,306,490	307,334,853
Treasury Stock, Shares at Cost	110,551,977	104,820,670

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue
Premium Income	$ 9,623.4	$ 9,481	$ 9,378.1
Net Investment Income	2,122.2	2,213.2	2,360.7
Net Investment Gain (Loss)	(15.7)	76.7	1,199.1
Other Income	261.1	242.9	224.2
Total Revenue	11,991	12,013.8	13,162.1
Benefits and Expenses
Benefits and Change in Reserves for Future Benefits	6,936.7	7,598.6	8,972.9
Commissions	1,086.4	1,038.1	1,057.3
Interest and Debt Expense	188.5	185	188.2
Cost Related to Early Retirement of Debt	4.2	67.3	0
Deferral of Acquisition Costs	(556.9)	(508.1)	(576.2)
Amortization of Deferred Acquisition Costs	591	586.1	606.1
Compensation Expense	1,089.5	975.2	953.2
Other Expenses	1,020.2	1,008.6	996.6
Total Benefits and Expenses	10,359.6	10,950.8	12,198.1
Income Before Income Tax	1,631.4	1,063	964
Income Tax
Current	473.5	212.8	(116.6)
Deferred	(156.3)	26	287.6
Total Income Tax	317.2	238.8	171
Net Income	$ 1,314.2	$ 824.2	$ 793
Net Income Per Common Share
Basic	$ 6.55	$ 4.04	$ 3.89
Assuming Dilution	$ 6.50	$ 4.02	$ 3.89

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Income	$ 1,314.2	$ 824.2	$ 793
Other Comprehensive Income (Loss)
Change in Net Unrealized Gain (Loss) on Securities Before Adjustment (net of tax expense (benefit) of $(1,890.8); $(346.9); $250.2)	(7,042.9)	(1,301.4)	983
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance (net of tax expense (benefit) of $1,100.8; $316.8; $(138.2))	4,056.9	1,195.9	(531.2)
Change in Net Gain (Loss) on Hedges (net of tax benefit of $19.2; $9.8; $23.8)	(71.4)	(36)	(90)
Change in Foreign Currency Translation Adjustment (net of tax expense (benefit) of $(0.1); $4.2; $(4.3))	(115.2)	(12.6)	20.3
Change in Unrecognized Pension and Postretirement Benefit Costs (net of tax expense (benefit) of $18.9; $42.1; $(34.8))	(61.9)	(134)	45.2
Total Other Comprehensive Income (Loss)	(3,110.7)	(20.1)	336.9
Comprehensive Income (Loss)	$ (1,796.5)	$ 804.1	$ 1,129.9

STATEMENT OF COMPREHENSIVE INCO

STATEMENT OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Change in Net Unrealized Gain on Securities Before Adjustment, Tax Expense (Benefit)	$ (1,890.8)	$ (346.9)	$ 250.2
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance, Tax Expense (Benefit)	1,100.8	316.8	(138.2)
Change in Net Gain (Loss) on Hedges, Tax Benefit	(19.2)	(9.8)	(23.8)
Other Comprehensive Income (Loss), Foreign Currency Translation, Tax Expense (Benefit)	(0.1)	4.2	(4.3)
Change in Unrecognized Pension and Postretirement Benefit Costs, Tax Expense (Benefit)	$ 18.9	$ 42.1	$ (34.8)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total		Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock
Balance at Beginning of Year at Dec. 31, 2019			$ 30.6	$ 2,348.1	$ 37.3	$ 10,728.7			$ (3,179.7)
Balance at Beginning of Year (Accounting Standards Update 2016-13) at Dec. 31, 2019							$ (18.9)	$ 10,709.8
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	28.1
Other Comprehensive Income (Loss)	$ 336.9				336.9
Net Income	793					793
Dividends to Stockholders (per common share: $1.26; $1.17; $1.14)						(233.2)
Purchases of Treasury Stock	0	[1]							0
Balance at End of Year at Dec. 31, 2020	10,871		30.7	2,376.2	374.2	11,269.6			(3,179.7)
Balance at End of Year (Accounting Standards Update 2016-13) at Dec. 31, 2020							0	11,269.6
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0	31.9
Other Comprehensive Income (Loss)	(20.1)				(20.1)
Net Income	824.2					824.2
Dividends to Stockholders (per common share: $1.26; $1.17; $1.14)						(240.6)
Purchases of Treasury Stock	(50)	[1]							(50)
Balance at End of Year at Dec. 31, 2021	11,416.4		30.7	2,408.1	354.1	11,853.2			(3,229.7)
Balance at End of Year (Accounting Standards Update 2016-13) at Dec. 31, 2021							$ 0	$ 11,853.2
Increase (Decrease) in Stockholders' Equity
Common Stock Activity			0.1	32.9
Other Comprehensive Income (Loss)	(3,110.7)				(3,110.7)
Net Income	1,314.2					1,314.2
Dividends to Stockholders (per common share: $1.26; $1.17; $1.14)						(255.3)
Purchases of Treasury Stock	(200.1)	[1]							(200.1)
Balance at End of Year at Dec. 31, 2022	$ 9,197.5		$ 30.8	$ 2,441	$ (2,756.6)	$ 12,912.1			$ (3,429.8)
[1]Includes commissions of $0.1 million for the year ended December 31, 2022.

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Common Stock, Dividends, Per Share, Cash Paid	$ 1.26	$ 1.17	$ 1.14

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flows from Operating Activities
Net Income	$ 1,314.2	$ 824.2	$ 793
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Change in Receivables	566	678	242.9
Deferral of Acquisition Costs	34.1	78	29.9
Change in Insurance Reserves and Liabilities	(282)	74.2	1,481.8
Change in Income Taxes	(58.8)	295.3	(31.3)
Change in Other Accrued Liabilities	(113.9)	11.3	160.1
Non-cash Components of Net Investment Income	(247)	(254.7)	(120.5)
Net Investment (Gain) Loss	15.7	(76.7)	(1,199.1)
Depreciation	110.5	119.8	113.6
Cash Related to Reinsurance Transaction	0	(456.8)	(1,087.2)
Amortization of the Cost of Reinsurance	63.8	79.1	2.6
Other, Net	16.1	15.8	83.5
Net Cash Provided by Operating Activities	1,418.7	1,387.5	469.3
Cash Flows from Investing Activities
Proceeds from Sales of Fixed Maturity Securities	559.5	442.5	990.8
Proceeds from Maturities of Fixed Maturity Securities	1,532.5	2,611.4	2,052.4
Proceeds from Sales and Maturities of Other Investments	445.9	403.1	237
Purchase of Fixed Maturity Securities	(2,835.3)	(4,106.3)	(3,169.6)
Purchase of Other Investments	(482.9)	(606.8)	(440.6)
Net Sales (Purchases) of Short-term Investments	(22.6)	76.5	(133.1)
Net Increase (Decrease) in Payables for Collateral on Investments	(50.8)	(50.7)	314.5
Net Purchases of Property and Equipment	(102.2)	(110.3)	(119.1)
Net Cash Used by Investing Activities	(955.9)	(1,340.6)	(267.7)
Cash Flows from Financing Activities
Short-term Debt Repayment	0	0	(400)
Issuance of Long-term Debt	349.2	588.1	494.1
Long-term Debt Repayment	(364)	(500)	(80)
Cost Related to Early Retirement of Debt	3.6	62.8	0
Issuance of Common Stock	4	3.4	4.4
Repurchase of Common Stock	(200.1)	(50)	0
Dividends Paid to Stockholders	(254.2)	(239.4)	(231.9)
Proceeds from Policyholder Account Deposits	119.8	128.1	138.4
Payments for Policyholder Account Withdrawals	(72)	(80.7)	(74.3)
Cash Received Related to Active Life Volatility Cover Agreement	5.2	40.4	62.1
Other, Net	(2.9)	4	(1.5)
Net Cash Used by Financing Activities	(418.6)	(168.9)	(88.7)
Net Increase (Decrease) in Cash and Bank Deposits	44.2	(122)	112.9
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance	75	197	84.1
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Ending Balance	$ 119.2	$ 75	$ 197

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting policies and error corrections [Abstract]
Significant Accounting Policies	Basis of Presentation : The accompanying consolidated financial statements of Unum Group and its subsidiaries (the Company) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). Such accounting principles differ from statutory accounting principles (see Note 16). Intercompany transactions have been eliminated. Description of Business : We are a leading provider of financial protection benefits in the United States, the United Kingdom, and Poland. Our products include disability, life, accident, critical illness, dental and vision, and other related services. We market our products primarily through the workplace. We have three principal operating business segments: Unum US, Unum International, and Colonial Life. Our other reporting segments are Closed Block and Corporate. See Note 13 for further discussion of our operating segments. Use of Estimates : The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Such estimates and assumptions could change in the future as more information becomes known, which could impact the amounts reported and disclosed herein. In accordance with standard practice, we regularly review the methodology used in the development of all key estimates. As a result of this review, in 2022, we updated our estimate of the unearned premium reserve for certain of our product lines to utilize a gross unearned premium reserve rather than a net unearned premium reserve. The effect of this change in estimate was to decrease 2022 premium income by $13.4 million and decrease commissions by $1.0 million. This resulted in a decrease to net income of $9.8 million and a decrease to both basic and diluted earnings per share by $0.05. Fixed Maturity Securities : Fixed maturity securities include long-term bonds and redeemable preferred stocks. Our fixed maturity securities are classified as available-for-sale and reported at fair value. Changes in the fair value of available-for-sale fixed maturity securities, except for amounts related to impairment and credit losses recognized in earnings, are reported as a component of other comprehensive income. These amounts are net of income tax and valuation adjustments to deferred acquisition costs and reserves for future policy and contract benefits which would have been recorded had the related unrealized gain or loss on these securities been realized. Realized investment gains or losses are based upon specific identification of the investments sold. Interest income is recorded as part of net investment income when earned, using an effective yield method giving effect to amortization of premium and accretion of discount. Included within fixed maturity securities are mortgage-backed and asset-backed securities. We recognize investment income on these securities using a constant effective yield based on projected prepayments of the underlying loans and the estimated economic life of the securities. Actual prepayment experience is reviewed periodically, and effective yields are recalculated when differences arise between prepayments originally projected and the actual prepayments received and currently projected. The effective yield is recalculated on a retrospective basis, and the adjustment is reflected in net investment income. For fixed maturity securities on which collection of investment income is uncertain, we discontinue the accrual of investment income and recognize investment income when interest and dividends are received. Payment terms specified for fixed maturity securities may include a prepayment penalty for unscheduled payoff of the investment. Prepayment penalties are recognized as investment income when received. In determining when a decline in fair value below amortized cost of a fixed maturity security is a credit loss, we evaluate available information, both positive and negative, in reaching our conclusions. In particular, we consider the strength of the issuer's balance sheet, its debt obligations and near-term funding requirements, cash flow and liquidity, the profitability of its core businesses, the availability of marketable assets which could be sold to increase liquidity, its industry fundamentals and regulatory environment, and its access to capital markets. Although all available and applicable factors are considered in our analysis, our expectation of recovering the entire amortized cost basis of the security, whether we intend to sell the security, whether it is more likely than not that we will be required to sell the security before recovery of its amortized cost, and whether the security is current on principal and interest payments are the most critical factors in determining whether impairments represent credit losses. The significance of the decline in value is also an important factor, but we generally do not record an impairment loss based solely on this factor, since often other more relevant factors will impact our evaluation of a security. For securities with a decline in fair value below amortized cost which we intend to sell or more likely than not will be required to sell before recovery in value, the amortized cost of the investment is written down to fair value through earnings, and an impairment loss is recognized in the current period. For securities that we believe are impaired and which we do not intend to sell and it is not more likely than not that we will be required to sell before recovery in value, we calculate an allowance for credit losses recognized in earnings which generally represents the difference between the amortized cost of the security and the present value of our best estimate of cash flows expected to be collected, discounted using the effective interest rate implicit in the security at the date of acquisition and limited by the difference between amortized cost and fair value of the security. For fixed maturity securities for which we have recognized an allowance for credit loss through earnings, if through subsequent evaluation there is a significant increase in expected cash flows, the allowance is reduced and is recognized as a reduction to credit losses in the current period. When an allowance for credit losses on a fixed maturity security is recognized, we designate non-accrual status for those securities. We reverse all previously accrued interest through interest income and use a cash basis method for recognizing any future payments received. See Notes 2 and 3. Mortgage Loans : Mortgage loans are generally held for investment and are carried at amortized cost less an allowance for expected credit losses. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. Prepayment penalties are recognized as investment income when received. For mortgage loans on which collection of interest income is uncertain, we discontinue the accrual of interest and recognize it in the period when an interest payment is received. We typically do not resume the accrual of interest on mortgage loans on nonaccrual status until there are significant improvements in the underlying financial condition of the borrower. We consider a loan to be delinquent if full payment is not received in accordance with the contractual terms of the loan. We evaluate each of our mortgage loans individually for impairment and assign an internal credit quality rating based on a comprehensive rating system used to evaluate the credit risk of the loan. Although all available and applicable factors are considered in our analysis, loan-to-value and debt service coverage ratios are the most critical factors in determining impairment. We estimate an allowance for credit losses that we expect to incur over the life of our mortgage loans using a probability of default method. For each loan, we estimate the probability that the loan will default before its maturity (probability of default) and the amount of the loss if the loan defaults (loss given default). These two factors result in an expected loss percentage that is applied to the amortized cost of each loan to determine the expected credit loss. As we are the original underwriter of the mortgage loans, the amortized cost generally equals the principal amount of the loan. We measure losses on defaults of our mortgage loans as the excess amortized cost of the mortgage loan over the fair value of the underlying collateral in the event that we foreclose on the loan or over the expected future cash flows of the loan if we retain the mortgage loan until payoff. We do not purchase mortgage loans with existing credit impairments. In estimating the probability of default, we consider historical experience, current market conditions, and reasonable and supportable forecasts about the future market conditions. We utilize our historical loan experience in combination with a large third-party industry database for a period of time that aligns with the average life of our loans based on the maturity dates of the loans and prepayment experience. Our model utilizes an industry database of the historical loss experience based on our actual portfolio characteristics such as loan-to-value, debt service coverage, collateral type, geography, and late payment history. In addition, because we actively manage our portfolio, we may extend the term of a loan in certain situations and will accordingly extend the maturity date in the estimate of probability of default. In estimating the loss given default, we primarily consider the type and value of collateral and secondarily the expected liquidation costs and time to recovery. The primary market factors that we consider in our forecast of future market conditions are gross domestic product, unemployment rates, interest rates, inflation, commercial real estate values, household formation, and retail sales. We also forecast certain loan specific factors such as growth in the fair value and net operating income of collateral by property type. We include our estimate of these factors over a two-year period and for the remainder of the loans’ estimated lives, adjusted for estimated prepayments. Past the two-year forecast period, we revert to the historical assumptions ratably by the end of the fifth year of the loan after which we utilize only historical assumptions. We utilize various scenarios to estimate our allowance for expected losses ranging from a base case scenario that reflects normal market conditions to a severe case scenario that reflects adverse market conditions. We will adjust our allowance each period to utilize the scenario or weighting of the scenarios that best reflects our view of current market conditions. Additions and reductions to our allowance for credit losses on mortgage loans are reported as a component of net investment gains and losses. See Note 3. Policy Loans : Policy loans are presented at the unpaid balances directly related to policyholders. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. Included in policy loans are $3,312.5 million and $3,373.7 million of policy loans ceded to reinsurers at December 31, 2022 and 2021, respectively. Other Long-term Investments : Other long-term investments are comprised primarily of private equity partnerships, real estate, perpetual preferred stock, common stock, and tax credit partnerships. Our investments in private equity partnerships are passive in nature and represent funds that are primarily invested in private credit, private equity, and real assets. We account for our investments in these partnerships using either the equity method or at fair value through net income depending on the level of ownership and the degree of our influence over partnership operating and financial policies. For investments in partnerships accounted for under the equity method, we report our investments at our share of the partnership's net asset value (NAV) and record our portion of partnership earnings as a component of net investment income. For investments in partnerships accounted for at fair value through net income, we also report our investments at our share of the partnership's NAV as a practical expedient for fair value with increases or decreases recorded as a component of net investment income. Distributions received from the funds arise from income generated by the underlying investments as well as the liquidation of the underlying investments and there is generally not a public market for these investments. Investment real estate is primarily comprised of property held for the production of income and property held for sale. Property held for the production of income is carried at cost less accumulated depreciation and any write-downs to fair value for impairment losses. Depreciation is recorded on a straight-line basis over the estimated useful life of the asset. A review for impairment is made whenever events or circumstances indicate that the carrying value may not be recoverable. An impairment loss is recognized when the carrying value of the property exceeds the expected undiscounted cash flows generated from the property, at which point the carrying value is written down to an estimated fair value. Real estate held for sale is carried at the lower of depreciated cost or fair value less estimated selling costs and is not further depreciated once classified as such. Our perpetual preferred stocks are valued at fair value, based on quoted market prices, where available. For preferred stocks not actively traded, fair values are estimated using values obtained from independent pricing services. Our investments in common stock are valued at fair value. Our shares of Federal Home Loan Bank (FHLB) common stock are carried at cost, which approximates fair value. Tax credit partnerships in which we have invested were formed for the purpose of investing in the construction and rehabilitation of low-income housing. Because the partnerships are structured such that there is no return of principal, the primary sources of investment return from our tax credit partnerships are tax credits and tax benefits derived from passive losses on the investments, both of which may exhibit variability over the life of the investment. These partnerships are accounted for using either the proportional or the effective yield method, depending primarily on whether the tax credits are guaranteed through a letter of credit, a tax indemnity agreement, or another similar arrangement. Tax credits received from these partnerships are reported in our consolidated statements of income as either a reduction of premium tax or a reduction of income tax. The amortization of the principal amount invested in these partnerships is reported as a component of either premium tax or income tax. See Notes 2 and 3 for further discussion of our other long-term investments. Short-term Investments : Short-term investments are carried at cost. Short-term investments include investments maturing within one year of purchase, such as corporate commercial paper and Treasury bills, bank term deposits, and other cash accounts and cash equivalents earning interest. Cash and Bank Deposits : Cash and bank deposits include cash on hand and non-interest bearing cash and deposit accounts. Derivative Financial Instruments : Derivative financial instruments (including certain derivative instruments embedded in other contracts) are recognized as either other long-term investments or other liabilities in our consolidated balance sheets and are reported at fair value. The accounting for a derivative depends on whether it has been designated and qualifies as part of a hedging relationship, and further, on the type of hedging relationship. To qualify for hedge accounting, at the inception of the hedging transaction, we formally document the risk management objective and strategy for undertaking the hedging transaction, as well as the designation of the hedge as either a fair value hedge or a cash flow hedge. Included in this documentation is how the hedging instrument is expected to hedge the designated risk(s) related to specific assets or liabilities on the balance sheet or to specific forecasted transactions as well as a description of the method that will be used to retrospectively and prospectively assess the hedging instrument's effectiveness. A derivative designated as a hedging instrument must be assessed as being highly effective in offsetting the designated risk(s) of the hedged item. Hedge effectiveness is formally assessed at inception and periodically throughout the life of the designated hedging relationship, using qualitative and quantitative methods. Qualitative methods include comparison of critical terms of the derivative to the hedged item. Quantitative methods include regression or other statistical analysis of changes in fair value or cash flows associated with the hedge relationship. Changes in the fair value of a derivative designated as a fair value hedge and changes in the fair value of the hedged item attributable to the risk being hedged are recognized in earnings as a component of net investment gain or loss during the period of change in fair value. For gains or losses on the derivative instrument that are excluded from the assessment of hedge effectiveness, those gains and losses are recognized in other comprehensive income or loss and amortized into earnings in the same income statement line as the related hedged item. The gain or loss on the termination of a fair value hedge is recognized in earnings as a component of net investment gain or loss during the period in which the termination occurs. When interest rate swaps are used in hedge accounting relationships, periodic settlements are recorded in the same income statement line as the related settlements of the hedged items. Changes in the fair value of a derivative designated as a cash flow hedge are reported in other comprehensive income and reclassified into earnings and reported on the same income statement line item as the hedged item and in the same period or periods during which the hedged item affects earnings. The gain or loss on the termination of an effective cash flow hedge is reported in other comprehensive income and reclassified into earnings and reported on the same income statement line item as the hedged item and in the same period or periods during which the hedged item affects earnings. Gains or losses on the termination of ineffective fair value or cash flow hedges are reported in earnings as a component of net investment gain or loss. In the event a hedged item is disposed of or the anticipated transaction being hedged is no longer likely to occur, we will terminate the related derivative and recognize the gain or loss on termination in current earnings as a component of net investment gain or loss. In the event a hedged item is disposed of subsequent to the termination of the hedging transaction, we reclassify any remaining gain or loss on the hedge out of accumulated other comprehensive income into earnings as a component of the same income statement line item wherein we report the gain or loss on disposition of the hedged item. For a derivative not designated as a hedging instrument, changes in the fair value of the derivative, together with the payment of periodic fees, if applicable, are recognized in the same income statement line item as the hedged item during the period of change in fair value. Cash flow activity from the settlement of derivative contracts is reported in the consolidated statements of cash flows as a component of proceeds from sales and maturities of other investments. In our consolidated balance sheets, we do not offset fair value amounts recognized for derivatives executed with the same counterparty under a master netting agreement and fair value amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral arising from those master netting agreements. See Notes 2, 3, and 4. Fair Value Measurement : Certain assets and liabilities are reported at fair value in our consolidated balance sheets and in our notes to our consolidated financial statements. We define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Therefore, fair value represents an exit price, not an entry price. The exit price objective applies regardless of our intent and/or ability to sell the asset or transfer the liability at the measurement date. Assets or liabilities with readily available actively quoted prices or for which fair value can be measured from actively quoted prices in active markets generally have more pricing observability and less judgment utilized in measuring fair value. When actively quoted prices are not available, fair values are based on quoted prices in markets that are not active, quoted prices for similar but not identical assets or liabilities, or other observable inputs. If observable inputs are not available, unobservable inputs and/or adjustments to observable inputs requiring management judgment are used to determine fair value. We categorize our assets and liabilities measured at estimated fair value into a three-level hierarchy, based on the significance of the inputs. The fair value hierarchy gives the highest priority to inputs which are unadjusted and represent quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). See Note 2. Allowance for Credit Losses on Premiums Receivable : We establish an allowance for credit losses on premiums receivable, which is deducted from the gross amount of our receivable balance, to present the net amount we expect to collect on this asset. The allowance is forward-looking in nature and is calculated based on considerations regarding both historical events and future expectations. Periodic changes in the allowance are recorded through earnings. The allowance on our premiums receivable is primarily determined using an aging analysis as well as historical lapse and delinquency rates by line of business, adjusted for key factors that may impact our future expectation of premium receipts such as changes in customer demographics, business practices, economic conditions, and product offerings. We write off premiums receivable amounts when determined to be uncollectible, which is based on various factors, including the aging of premiums receivable past the due date and specific communication with customers. At December 31, 2022 and 2021, the allowance for expected credit losses on premium receivables was $32.5 million and $34.2 million, respectively, on gross premium receivables of $557.6 million and $530.7 million, respectively. The allowance decreased $1.7 million during the year ended December 31, 2022, and was driven primarily by improvements in the age of premiums receivable. The allowance decreased $4.6 million during the year ended December 31, 2021, driven primarily by improvements in the age of premiums receivable and improvements in unemployment levels. Deferred Acquisition Costs : Incremental direct costs associated with the successful acquisition of new or renewal insurance contracts have been deferred. Such costs include commissions, other agency compensation, certain selection and policy issue expenses, and certain field expenses. Acquisition costs that do not vary with the production of new business, such as commissions on group products which are generally level throughout the life of the policy, are excluded from deferral. Deferred acquisition costs are subject to recoverability testing at the time of policy issue and loss recognition testing in subsequent years. Deferred acquisition costs related to non-interest sensitive policies are amortized in proportion to the premium income we expect to receive over the lives of the policies. Deferred acquisition costs related to interest sensitive policies are amortized over the lives of the policies in relation to the present value of estimated gross profits from surrender charges, mortality margins, investment returns, and expense margins. Deviations from projections result in a change to the rate of amortization in the period during which such events occur. Generally, the amortization periods for these policies approximate the estimated lives of the policies. For certain products, policyholders can elect to modify product benefits, features, rights, or coverages by exchanging a contract for a new contract or by amendment, endorsement, or rider to a contract, or by the election of a feature or coverage within a contract. These transactions are known as internal replacement transactions. Internal replacement transactions wherein the modification does not substantially change the policy are accounted for as continuations of the replaced contracts. Unamortized deferred acquisition costs from the original policy continue to be amortized over the expected life of the new policy, and the costs of replacing the policy are accounted for as policy maintenance costs and expensed as incurred. Internal replacement transactions, principally on group contracts, that result in a policy that is substantially changed are accounted for as an extinguishment of the original policy and the issuance of a new policy. Unamortized deferred acquisition costs on the original policy that was replaced are immediately expensed, and the costs of acquiring the new policy are capitalized and amortized in accordance with our accounting policies for deferred acquisition costs. Loss recognition and recoverability testing is performed on an annual basis, or more frequently if appropriate, using best estimate assumptions as to future experience as of the date of the test. Insurance contracts are grouped for each major product line within a segment when we perform the loss recognition and recoverability tests. If loss recognition or recoverability testing indicates that deferred acquisition costs are not recoverable, the deficiency is charged to expense. Goodwill : Goodwill is the excess of the amount paid to acquire a business over the fair value of the net assets acquired. We review the carrying amount of goodwill for impairment on an annual basis, or more frequently if events or changes in circumstances indicate that the carrying amount might not be recoverable. Goodwill impairment testing compares the fair value of a reporting unit with its carrying amount, including goodwill. If the fair value of the reporting unit to which the goodwill relates is less than the carrying amount of the reporting unit, an impairment charge is recognized for the amount by which the carrying amount exceeds the fair value of the reporting unit in an amount not to exceed the total amount of goodwill allocated to the reporting unit. Property and Equipment : Property and equipment is reported at cost less accumulated depreciation, which is calculated on the straight-line method over the estimated useful life. The accumulated depreciation for property and equipment was $1,328.7 million and $1,259.6 million as of December 31, 2022 and 2021, respectively. Value of Business Acquired : Value of business acquired represents the present value of future profits recorded in connection with the acquisition of a block of insurance policies. The asset is amortized based upon expected future premium income for non-interest sensitive insurance policies and estimated future gross profits from surrender charges, mortality margins, investment returns, and expense margins for interest sensitive insurance policies. The value of business acquired, which is included in other assets in our consolidated balance sheets, was $62.9 million and $73.1 million at December 31, 2022 and 2021, respectively. The accumulated amortization for value of business acquired was $150.3 million and $157.7 million as of December 31, 2022 and 2021, respectively. The amortization of value of business acquired, which is included in other expenses in the consolidated statements of income, was $4.9 million, $5.7 million, and $6.1 million for the years ended December 31, 2022, 2021, and 2020, respectively. We periodically review the carrying amount of value of business acquired using the same methods used to evaluate deferred acquisition costs. Policy and Contract Benefits : Policy and contract benefits represent amounts paid and expected to be paid based on reported losses and estimates of incurred but not reported losses for non-interest sensitive life and accident and health products. For interest sensitive products, benefits are the amounts paid and expected to be paid on insured claims in excess of the policyholders' policy fund balances. Reserves for Future Policy and Contract Benefits : Policy reserves represent future policy and contract benefits for claims not yet incurred. Policy reserves for non-interest sensitive life and accident and health products are determined using the net level premium method. The reserves are calculated based upon assumptions as to interest, persistency, morbidity, and mortality that were appropriate at the date of issue. Discount rate assumptions are based on actual and expected net investment returns. Persistency assumptions are based on our actual historical experience adjusted for future expectations. Claim incidence and claim resolution rate assumptions related to morbidity and mortality are based on actual experience or industry standards adjusted as appropriate to reflect our actual experience and future expectations. The assumptions vary by plan, year of issue, and policy duration and include a provision for adverse deviation. Policy reserves for group single premium annuities are developed on a net single premium method. The reserves are calculated based on assumptions as to interest, mortality, and retirement that were appropriate at the date of issue. Mortality assumptions are based upon industry standards adjusted as appropriate to reflect our actual experience and future expectations. The assumptions vary by year of issue. Policy reserves for interest sensitive products are principally policyholder account values resulting from customer deposits and interest credited less cost of insurance, policy administration expenses, surrender charges, and customer withdrawals. Policy reserves require ongoing loss recognition testing. We perform loss recognition tests on our policy reserves annually, or more frequently if appropriate, using best estimate assumptions as of the date of the test, without a provision for adverse deviation. We group the policy reserves for each major product line within a segment when we perform the loss recognition tests. If the policy reserves determined using these best estimate assumptions are higher than our existing policy reserves net of any deferred acquisition cost balance, the existing policy reserves are increased or deferred acquisition costs are reduced to immediately recognize the deficiency. This becomes the new basis for policy reserves going forward, subject to future loss recognition testing. Claim reserves represent future policy and contract benefits for claims that have been incurred or are estimated to have been incurred but not yet reported to us. Our claim reserves relate primarily to disability and long-term care policies and are calculated based on assumptions as to interest and claim resolution rates that are currently appropriate. Claim resolution rate assumptions are based on our actual experience. The interest rate assumptions used for discounting claim reserves are based on projected portfolio yield rates, after consideration for defaults and investment expenses, for the assets supporting the liabilities for the various product lines. Unlike policy reserves for which assumptions are generally established and locked in at the time of policy issuance, claim reserves are subject to revision as current claim experience and projections of future factors affecting claim experience change. Claim reserves do not include a provision for adverse deviation. See Note 6. Other Policyholders' Funds : Other policyholders' funds represent customer deposits plus interest credited at contract rates. We control interest rate risk by investing in quality assets which have an aggregate duration that closely matches the expected duration of life liabilities. Income Tax : Deferred taxes reflect the net tax effects of temporary differences between the carrying amounts of assets

Fair Values of Financial Instru

Fair Values of Financial Instruments	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Values of Financial Instruments	Fair Value Measurements for Financial Instruments Carried at Fair Value We report fixed maturity securities, which are classified as available-for-sale securities, derivative financial instruments, and unrestricted equity securities at fair value in our consolidated balance sheets. We report our investments in private equity partnerships at our share of the partnerships' NAV per share or its equivalent as a practical expedient for fair value. See Note 1. The degree of judgment utilized in measuring the fair value of financial instruments generally correlates to the level of pricing observability. Financial instruments with readily available active quoted prices or for which fair value can be measured from actively quoted prices in active markets generally have more pricing observability and less judgment utilized in measuring fair value. An active market for a financial instrument is a market in which transactions for an asset or a similar asset occur with sufficient frequency and volume to provide pricing information on an ongoing basis. A quoted price in an active market provides the most reliable evidence of fair value and should be used to measure fair value whenever available. Conversely, financial instruments rarely traded or not quoted have less observability and are measured at fair value using valuation techniques that require more judgment. Pricing observability is generally impacted by a number of factors, including the type of financial instrument, whether the financial instrument is new to the market and not yet established, the characteristics specific to the transaction, and overall market conditions. We classify financial instruments in accordance with a fair value hierarchy consisting of three levels based on the observability of valuation inputs: • Level 1 - the highest category of the fair value hierarchy classification wherein inputs are unadjusted and represent quoted prices in active markets for identical assets or liabilities at the measurement date. • Level 2 - valued using inputs (other than prices included in Level 1) that are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument's anticipated life. • Level 3 - the lowest category of the fair value hierarchy and reflects the judgment of management regarding what market participants would use in pricing assets or liabilities at the measurement date. Financial assets and liabilities categorized as Level 3 are generally those that are valued using unobservable inputs to extrapolate an estimated fair value. Valuation Methodologies of Financial Instruments Measured at Fair Value Valuation techniques used for assets and liabilities accounted for at fair value are generally categorized into three types. The market approach uses prices and other relevant information from market transactions involving identical or comparable assets or liabilities. The income approach converts future amounts, such as cash flows or earnings, to a single present amount, or a discounted amount. The cost approach is based upon the amount that currently would be required to replace the service capacity of an asset, or the current replacement cost. We use valuation techniques that are appropriate in the circumstances and for which sufficient data are available that can be obtained without undue cost and effort. In some cases, a single valuation technique will be appropriate (for example, when valuing an asset or liability using quoted prices in an active market for identical assets or liabilities). In other cases, multiple valuation techniques will be appropriate. If we use multiple valuation techniques to measure fair value, we evaluate and weigh the results, as appropriate, considering the reasonableness of the range indicated by those results. A fair value measurement is the point within that range that is most representative of fair value in the circumstances. The selection of the valuation method(s) to apply considers the definition of an exit price and depends on the nature of the asset or liability being valued. For assets and liabilities accounted for at fair value, we generally use valuation techniques consistent with the market approach, and to a lesser extent, the income approach. We believe the market approach provides more observable data than the income approach, considering the type of investments we hold. Our fair value measurements could differ significantly based on the valuation technique and available inputs. When using a pricing service, we obtain the vendor's pricing documentation to ensure we understand their methodologies. We periodically review and approve the selection of our pricing vendors to ensure we are in agreement with their current methodologies. When markets are less active, brokers may rely more on models with inputs based on the information available only to the broker. Our internal investment management professionals, which include portfolio managers and analysts, monitor securities priced by brokers and evaluate their prices for reasonableness based on benchmarking to available primary and secondary market information. In weighing a broker quote as an input to fair value, we place less reliance on quotes that do not reflect the result of market transactions. We also consider the nature of the quote, particularly whether it is a bid or market quote. If prices in an inactive market do not reflect current prices for the same or similar assets, adjustments may be necessary to arrive at fair value. When relevant market data is unavailable, which may be the case during periods of market uncertainty, the income approach can, in suitable circumstances, provide a more appropriate fair value. During 2022, we have applied valuation approaches and techniques on a consistent basis to similar assets and liabilities and consistent with those approaches and techniques used at year end 2021. Fixed Maturity and Equity Securities We use observable and unobservable inputs in measuring the fair value of our fixed maturity and equity securities. For securities categorized as Level 1, fair values equal active Trade Reporting and Compliance Engine (TRACE) pricing or unadjusted market maker prices. For securities categorized as Level 2 or Level 3, inputs that may be used in valuing each class of securities at any given time period are disclosed below. Actual inputs used to determine fair values will vary for each reporting period depending on the availability of inputs which may, at times, be affected by the lack of market liquidity. Level 2 Level 3 Instrument Observable Inputs Unobservable Inputs United States Government and Government Agencies and Authorities Valuation Method Principally the market approach Not applicable Valuation Techniques / Inputs Prices obtained from external pricing services States, Municipalities, and Political Subdivisions Valuation Method Principally the market approach Principally the market approach Valuation Techniques / Inputs Prices obtained from external pricing services Analysis of similar bonds, adjusted for comparability Relevant reports issued by analysts and rating agencies Audited financial statements Level 2 Level 3 Instrument Observable Inputs Unobservable Inputs Foreign Governments Valuation Method Principally the market approach Principally the market approach Valuation Techniques / Inputs Prices obtained from external pricing services Analysis of similar bonds, adjusted for comparability Non-binding broker quotes Call provisions Public Utilities Valuation Method Principally the market and income approaches Principally the market and income approaches Valuation Techniques / Inputs Prices obtained from external pricing services Change in benchmark reference Public Utilities - Continued Non-binding broker quotes Analysis of similar bonds, adjusted for comparability Benchmark yields Discount for size - illiquidity Transactional data for new issuances and secondary trades Volatility of credit Security cash flows and structures Lack of marketability Recent issuance / supply Audited financial statements Security and issuer level spreads Security creditor ratings/maturity/capital structure/optionality Public covenants Comparative bond analysis Relevant reports issued by analysts and rating agencies Mortgage/Asset-Backed Securities Valuation Method Principally the market and income approaches Principally the market approach Valuation Techniques / Inputs Prices obtained from external pricing services Analysis of similar bonds, adjusted for comparability Non-binding broker quotes Prices obtained from external pricing services Security cash flows and structures Underlying collateral Prepayment speeds/loan performance/delinquencies Relevant reports issued by analysts and rating agencies Audited financial statements Level 2 Level 3 Instrument Observable Inputs Unobservable Inputs All Other Corporate Bonds Valuation Method Principally the market and income approaches Principally the market and income approaches Valuation Techniques / Inputs Prices obtained from external pricing services Change in benchmark reference Non-binding broker quotes Discount for size - illiquidity Benchmark yields Volatility of credit Transactional data for new issuances and secondary trades Lack of marketability Security cash flows and structures Prices obtained from external pricing services Recent issuance / supply Security and issuer level spreads Security creditor ratings/maturity/capital structure/optionality All Other Corporate Bonds - Continued Public covenants Comparative bond analysis Relevant reports issued by analysts and rating agencies Audited financial statements Redeemable Preferred Stocks Valuation Method Principally the market approach Principally the market approach Valuation Techniques / Inputs Non-binding broker quotes Financial statement analysis Benchmark yields Comparative bond analysis Call provisions Relevant reports issued by analysts and rating agencies Audited financial statements Perpetual Preferred and Equity Securities Valuation Method Principally the market approach Principally the market and income approaches Valuation Techniques / Inputs Prices obtained from external pricing services Financial statement analysis Non-binding broker quotes The management of our investment portfolio includes establishing pricing policy and reviewing the reasonableness of sources and inputs used in developing pricing. We review all prices that vary between multiple pricing vendors by a threshold that is outside a normal market range for the asset type. In the event we receive a vendor's market price that does not appear reasonable based on our market analysis, we may challenge the price and request further information about the assumptions and methodologies used by the vendor to price the security. We may change the vendor price based on a better data source such as an actual trade. We also review all prices that did not change from the prior month to ensure that these prices are within our expectations. The overall valuation process for determining fair values may include adjustments to valuations obtained from our pricing sources when they do not represent a valid exit price. These adjustments may be made when, in our judgment and considering our knowledge of the financial conditions and industry in which the issuer operates, certain features of the financial instrument require that an adjustment be made to the value originally obtained from our pricing sources. These features may include the complexity of the financial instrument, the market in which the financial instrument is traded, counterparty credit risk, credit structure, concentration, or liquidity. Additionally, an adjustment to the price derived from a model typically reflects our judgment of the inputs that other participants in the market for the financial instrument being measured at fair value would consider in pricing that same financial instrument. In the event an asset is sold, we test the validity of the fair value determined by our valuation techniques by comparing the selling price to the fair value determined for the asset in the immediately preceding month end reporting period. Certain of our investments do not have readily determinable market prices and/or observable inputs or may at times be affected by the lack of market liquidity. For these securities, we use internally prepared valuations, including valuations based on estimates of future profitability, to estimate the fair value. Additionally, we may obtain prices from independent third-party brokers to aid in establishing valuations for certain of these securities. Key assumptions used by us to determine fair value for these securities include risk free interest rates, risk premiums, performance of underlying collateral (if any), and other factors involving significant assumptions which may or may not reflect those of an active market. The parameters and inputs used to validate a price on a security may be adjusted for assumptions about risk and current market conditions on a quarter to quarter basis, as certain features may be more significant drivers of valuation at the time of pricing. Changes to inputs in valuations are not changes to valuation methodologies; rather, the inputs are modified to reflect direct or indirect impacts on asset classes from changes in market conditions. At December 31, 2022, approximately 13.0 percent of our fixed maturity securities were valued using active trades from TRACE pricing or market maker prices for which there was current market activity in that specific security (comparable to receiving one binding quote). The prices obtained were not adjusted, and the assets were classified as Level 1. The remaining 87.0 percent of our fixed maturity securities were valued based on non-binding quotes or other observable and unobservable inputs, as discussed below: • 71.0 percent of our fixed maturity securities were valued based on prices from pricing services that generally use observable inputs such as prices for securities or comparable securities in active markets in their valuation techniques. These assets were classified as Level 2. • 15.1 percent of our fixed maturity securities were valued based on one or more non-binding broker quotes, if validated by observable market data. When only one price is available, it is used if observable inputs and analysis confirms that it is appropriate. These assets, for which we were able to validate the price using other observable market data, were classified as Level 2. • 0.9 percent of our fixed maturity securities were valued based on prices of comparable securities, internal models, or pricing services or other non-binding quotes with no other observable market data. These assets were classified as either Level 2 or Level 3, with the categorization dependent on whether there was other observable market data. Derivatives Fair values for derivatives other than embedded derivatives in modified coinsurance arrangements are based on market quotes or pricing models and represent the net amount of cash we would have paid or received if the contracts had been settled or closed as of the last day of the period. Credit risk related to the counterparty and the Company is considered in determining the fair values of these derivatives. However, since we have collateralization agreements in place with each counterparty which limits our exposure, any credit risk is immaterial. Therefore, we determined that no adjustments for credit risk were required as of December 31, 2022 or 2021. Fair values for our embedded derivative in a modified coinsurance arrangement are estimated using internal pricing models and represent the hypothetical value of the duration mismatch of assets and liabilities, interest rate risk, and third party credit risk embedded in the modified coinsurance arrangement. We consider transactions in inactive markets to be less representative of fair value. We use all available observable inputs when measuring fair value, but when significant unobservable inputs are used, we classify these assets or liabilities as Level 3. Private Equity Partnerships Our private equity partnerships represent funds that are primarily invested in private credit, private equity, and real assets, as described below. Distributions received from the funds arise from income generated by the underlying investments as well as the liquidation of the underlying investments. There is generally not a public market for these investments. The following tables present additional information about our private equity partnerships, including commitments for additional investments which may or may not be funded: December 31, 2022 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 239.3 Not redeemable $ 90.9 35.7 Initial 2 year lock on each new investment / Quarterly after 2 year lock with 90 days notice 13.4 Total Private Credit 275.0 104.3 Private Equity (b) 453.6 Not redeemable 377.2 31.7 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 39.1 Total Private Equity 485.3 416.3 Real Assets (c) 373.9 Not redeemable 256.3 60.1 Quarterly / 90 days notice — Total Real Assets 434.0 256.3 Total Partnerships $ 1,194.3 $ 776.9 December 31, 2021 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 240.6 Not redeemable $ 143.7 38.8 Initial 2 year lock on each new investment / Quarterly after 2 year lock with 90 days notice 6.8 Total Private Credit 279.4 150.5 Private Equity (b) 365.8 Not redeemable 274.3 18.8 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 50.3 Total Private Equity 384.6 324.6 Real Assets (c) 256.2 Not redeemable 278.1 58.4 Quarterly / 90 days notice — Total Real Assets 314.6 278.1 Total Partnerships $ 978.6 $ 753.2 (a) Private Credit - The limited partnerships described in this category employ various investment strategies, generally providing direct lending or other forms of debt financing including first-lien, second-lien, mezzanine, and subordinated loans. The limited partnerships have credit exposure to corporates, physical assets, and/or financial assets within a variety of industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail) in North America and, to a lesser extent, outside of North America. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 55 percent in the next 3 years, 34 percent during the period from 3 to 5 years, 9 percent during the period from 5 to 10 years, and 2 percent during the period from 10 to 15 years. (b) Private Equity - The limited partnerships described in this category employ various strategies generally investing in controlling or minority control equity positions directly in companies and/or assets across various industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail), primarily in private markets within North America and, to a lesser extent, outside of North America. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 35 percent in the next 3 years, 19 percent during the period from 3 to 5 years, 40 percent during the period from 5 to 10 years, and 6 percent during the period from 10 to 15 years. (c) Real Assets - The limited partnerships described in this category employ various strategies, which include investing in the equity and/or debt financing of physical assets, including infrastructure (energy, power, water/wastewater, communications), transportation (including airports, ports, toll roads, aircraft, railcars) and real estate in North America, Europe, South America, and Asia. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 22 percent in the next 3 years, 28 percent during period from 3 to 5 years and 50 percent during the period from 5 to 10 years. We record changes in our share of net asset value of the partnerships in net investment income. We receive financial information related to our investments in partnerships and generally record investment income on a one-quarter lag in accordance with our accounting policy. The following tables present information about financial instruments measured at fair value on a recurring basis by fair value level, based on the observability of the inputs used. December 31, 2022 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ 81.7 $ 416.5 $ — $ — $ 498.2 States, Municipalities, and Political Subdivisions 8.7 3,448.3 0.2 — 3,457.2 Foreign Governments — 827.1 — — 827.1 Public Utilities 160.1 4,796.8 — — 4,956.9 Mortgage/Asset-Backed Securities — 551.3 22.0 — 573.3 All Other Corporate Bonds 4,268.6 20,097.3 158.7 — 24,524.6 Redeemable Preferred Stocks — 3.5 — — 3.5 Total Fixed Maturity Securities 4,519.1 30,140.8 180.9 — 34,840.8 Other Long-term Investments Derivatives Forwards — 5.6 — — 5.6 Foreign Exchange Contracts — 83.5 — — 83.5 Total Derivatives — 89.1 — — 89.1 Perpetual Preferred and Equity Securities — 9.6 16.2 — 25.8 Private Equity Partnerships — — — 1,194.3 1,194.3 Total Other Long-term Investments — 98.7 16.2 1,194.3 1,309.2 Total Financial Instrument Assets Carried at Fair Value $ 4,519.1 $ 30,239.5 $ 197.1 $ 1,194.3 $ 36,150.0 Liabilities Other Liabilities Derivatives Forwards $ — $ 48.5 $ — $ — $ 48.5 Foreign Exchange Contracts — 25.5 — — 25.5 Embedded Derivative in Modified Coinsurance Arrangement — — 13.9 — 13.9 Total Derivatives — 74.0 13.9 — 87.9 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 74.0 $ 13.9 $ — $ 87.9 December 31, 2021 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ — $ 580.1 $ — $ — $ 580.1 States, Municipalities, and Political Subdivisions — 4,714.1 13.4 — 4,727.5 Foreign Governments — 1,125.8 20.8 — 1,146.6 Public Utilities 230.8 6,140.7 44.5 — 6,416.0 Mortgage/Asset-Backed Securities — 451.1 187.2 — 638.3 All Other Corporate Bonds 3,288.7 25,673.2 861.5 — 29,823.4 Redeemable Preferred Stocks — 4.1 — — 4.1 Total Fixed Maturity Securities 3,519.5 38,689.1 1,127.4 — 43,336.0 Other Long-term Investments Derivatives Foreign Exchange Contracts — 39.5 — — 39.5 Total Derivatives — 39.5 — — 39.5 Perpetual Preferred and Equity Securities — 27.9 5.8 — 33.7 Private Equity Partnerships — — — 978.6 978.6 Total Other Long-term Investments — 67.4 5.8 978.6 1,051.8 Total Financial Instrument Assets Carried at Fair Value $ 3,519.5 $ 38,756.5 $ 1,133.2 $ 978.6 $ 44,387.8 Liabilities Other Liabilities Derivatives Foreign Exchange Contracts $ — $ 35.0 $ — $ — $ 35.0 Embedded Derivative in Modified Coinsurance Arrangement — — 30.1 — 30.1 Total Derivatives — 35.0 30.1 — 65.1 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 35.0 $ 30.1 $ — $ 65.1 Changes in assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) are as follows: Year Ended December 31, 2022 Fair Value Beginning Total Realized and Purchases Sales/Maturities Level 3 Transfers Fair Value End of Change in Unrealized Earnings OCI Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities States, Municipalities, and Political Subdivisions $ 13.4 $ — $ (0.1) $ — $ — $ 0.3 $ (13.4) $ 0.2 $ (0.1) $ — Foreign Governments 20.8 — (0.8) — (20.0) — — — (0.8) — Public Utilities 44.5 — (2.8) — (12.8) 15.6 (44.5) — (2.8) — Mortgage/Asset-Backed Securities 187.2 — (0.3) 20.7 (10.6) — (175.0) 22.0 (0.3) — All Other Corporate Bonds 861.5 — (32.0) 25.3 (102.3) 161.9 (755.7) 158.7 (32.0) — Total Fixed Maturity Securities 1,127.4 — (36.0) 46.0 (145.7) 177.8 (988.6) 180.9 (36.0) — Perpetual Preferred and Equity Securities 5.8 3.0 — 7.1 — 0.3 — 16.2 — 3.0 Embedded Derivative in Modified Coinsurance Arrangement (30.1) 16.2 — — — — — (13.9) — 16.2 Year Ended December 31, 2021 Fair Value Beginning Total Realized and Purchases Sales/Maturities Level 3 Transfers Fair Value End of Change in Unrealized Earnings OCI Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities States, Municipalities, and Political Subdivisions $ 15.5 $ — $ (2.1) $ — $ — $ — $ — $ 13.4 $ (2.1) $ — Foreign Governments 21.8 — (1.0) — — — — 20.8 (1.0) — Public Utilities 185.7 — (2.3) — (44.0) 36.0 (130.9) 44.5 (2.3) — Mortgage/Asset-Backed Securities 81.3 — (96.0) — (72.3) 274.2 — 187.2 (96.0) — All Other Corporate Bonds 943.1 — (24.6) 249.9 (80.2) 77.6 (304.3) 861.5 (24.6) — Total Fixed Maturity Securities 1,247.4 — (126.0) 249.9 (196.5) 387.8 (435.2) 1,127.4 (126.0) — Perpetual Preferred and Equity Securities 4.7 0.1 — 1.0 — — — 5.8 — 0.1 Embedded Derivative in Modified Coinsurance Arrangement (39.8) 9.7 — — — — — (30.1) — 9.7 Realized and unrealized investment gains and losses presented in the preceding tables represent gains and losses only for the time during which the applicable financial instruments were classified as Level 3. The transfers between levels resulted primarily from a change in observability of three inputs used to determine fair values of the securities transferred: (1) transactional data for new issuance and secondary trades, (2) broker/dealer quotes and pricing, primarily related to changes in the level of activity in the market and whether the market was considered orderly, and (3) comparable bond metrics from which to perform an analysis. For fair value measurements of financial instruments that were transferred either into or out of Level 3, we reflect the transfers using the fair value at the beginning of the period. We believe this allows for greater transparency, as all changes in fair value that arise during the reporting period of the transfer are disclosed as a component of our Level 3 reconciliation. The table below provides quantitative information regarding the significant unobservable inputs used in Level 3 fair value measurements derived from internal models. Unobservable inputs for fixed maturity securities are weighted by the fair value of the securities. Certain securities classified as Level 3 are excluded from the table below due to limitations in our ability to obtain the underlying inputs used by external pricing sources. December 31, 2022 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 15.3 Market Approach Volatility of Credit Market Convention (a) (b) 5.41% - 5.41% / 5.41% Priced at Par Value Perpetual Preferred and Equity Securities 16.2 Market Approach Market Convention (b) Priced at Cost, Owner's Equity, or Most Recent Round Embedded Derivative in Modified Coinsurance Arrangement (13.9) Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (d) Actuarial Assumptions 0.6% December 31, 2021 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 111.8 Market Approach Volatility of Credit Lack of Marketability (a) (c) 6.30% - 6.30% / 6.30% 0.14% - 0.73% / 0.51% Perpetual Preferred and Equity Securities 5.8 Market Approach Market Convention (b) Priced at Cost or Owner's Equity Embedded Derivative in Modified Coinsurance Arrangement (30.1) Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (d) Actuarial Assumptions (a) Represents basis point adjustments for credit-specific factors (b) Represents a decision to price based on par value, cost, owner's equity, or the price of the most recent capital funding round when limited data is available (c) Represents basis point adjustments to apply a discount due to the illiquidity of an investment (d) Represents various actuarial assumptions required to derive the liability cash flows. Fair value of embedded derivative is most often driven by the change in the weighted average credit spread to the swap curve for the assets backing the hypothetical loan Other than market convention, the impact of isolated decreases in unobservable inputs will result in a higher estimated fair value, whereas isolated increases in unobservable inputs will result in a lower estimated fair value. The unobservable input for market convention is not sensitive to input movements. The projected liability cash flows used in the fair value measurement of our Level 3 embedded derivative are based on expected claim payments. If claim payments increase, the projected liability cash flows will increase, resulting in a decrease in the fair value of the embedded derivative. Decreases in projected liability cash flows will result in an increase in the fair value of the embedded derivative. Fair Value Measurements for Financial Instruments Not Carried at Fair Value The methods and assumptions used to estimate fair values of financial instruments not carried at fair value are discussed as follows: Mortgage Loans: Fair value of newly originated, seasoned performing, or sub-performing but likely to continue cash flowing loans are calculated using a discounted cash flow analysis. Loans’ cash flows are modeled and appropriately discounted by a rate based on current yields and credit spreads. For sub and non-performing loans where there is some probability the loan will not continue to pay, a price based approach would be used to estimate the loan’s value in the open market utilizing current transaction information from similar loans. Policy Loans: Fair values for policy loans, net of reinsurance ceded, are estimated using discounted cash flow analyses and interest rates currently being offered to policyholders with similar policies. Carrying amounts for ceded policy loans, which equal $3,312.5 million and $3,373.7 million as of December 31, 2022 and 2021, respectively, approximate fair value and are reported on a gross basis in our consolidated balance sheets. A change in interest rates for ceded policy loans will not impact our financial position because the benefits and risks are fully ceded to reinsuring counterparties. Miscellaneous Long-term Investments: Carrying amounts for tax credit partnerships equal the unamortized balance of our contractual commitments and approximate fair value. Our shares of Federal Home Loan Bank (FHLB) common stock are carried at cost, which approximates fair value. Long-term Debt: Fair values for long-term debt are obtained from independent pricing services or discounted cash flow analyses based on current incremental borrowing rates for similar types of borrowing arrangements. FHLB Funding Agreements: Funding agreements with the FHLB represent cash advances used for the purpose of investing in fixed maturity securities. Carrying amounts approximate fair value. Unfunded Commitments to Investment Partnerships: Unfunded equity commitments represent amounts that we have committed to fund certain investment partnerships. These commitments are legally binding, subject to the partnerships meeting specified conditions. Carrying amounts of these financial instruments approximate fair value. The following table presents the carrying amounts and estimated fair values of our financial instruments not measured at fair value and indicates the level in the fair value hierarchy of the estimated fair value measurement based on the observability of the inputs used: December 31, 2022 Estimated Fair Value Level 1 Level 2 Level 3 Total Carrying Value (in millions of dollars) Assets Mortgage Loans $ — $ 2,159.5 $ — $ 2,159.5 $ 2,435.4 Policy Loans — — 3,677.0 3,677.0 3,601.2 Other Long-term Investments Miscellaneous Long-term Investments — 17.1 1.3 18.4 18.4 Total Financial Instrument Assets Not Carried at Fair Value $ — $ 2,176.6 $ 3,678.3 $ 5,854.9 $ 6,055.0 Liabilities Long-term Debt $ 2,288.9 $ 783.1 $ — $ 3,072.0 $ 3,427.8 Other Liabilities Unfunded Commitments — 0.7 — 0.7 0.7 Payable for Collateral on FHLB Funding Agreements — 99.1 — 99.1 99.1 Total Financial Instrument Liabilities Not Carried at Fair Value $ 2,288.9 $ 882.9 $ — $ 3,171.8 $ 3,527.6 December 31, 2021 Estimated Fair Value Level 1 Level 2 Level 3 Total Carrying Value (in millions of dollars) Assets Mortgage L

Investments

Investments	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Investments	65% <= 75% 937.2 38.5 1,076.8 42.0 > 75% <= 85% 75.0 3.1 114.9 4.5 > 85% 33.6 1.4 22.6 0.9 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property The following table presents the amortized cost of our mortgage loans by year of origination and credit quality indicators for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 Prior to 2018 2018 2019 2020 2021 2022 Total (in millions of dollars) Internal Rating AA $ 53.8 $ 27.5 $ 11.1 $ — $ — $ — $ 92.4 A 485.0 123.3 96.8 35.9 80.6 24.0 845.6 BBB 534.0 219.8 236.9 134.0 275.8 64.6 1,465.1 BB 35.7 5.9 — — — — 41.6 Total Amortized Cost 1,108.5 376.5 344.8 169.9 356.4 88.6 2,444.7 Allowance for credit losses (4.3) (1.8) (1.3) (0.6) (0.8) (0.5) (9.3) Carrying Amount $ 1,104.2 $ 374.7 $ 343.5 $ 169.3 $ 355.6 $ 88.1 $ 2,435.4 Loan-to-Value Ratio (1) <=65% $ 782.6 $ 189.0 $ 193.9 $ 81.3 $ 128.9 $ 16.9 $ 1,392.6 >65<=75% 230.2 181.6 150.9 80.1 227.5 71.7 942.0 >75%<=85% 67.5 — — 8.5 — — 76.0 >85% 28.2 5.9 — — — — 34.1 Total Amortized Cost 1,108.5 376.5 344.8 169.9 356.4 88.6 2,444.7 Allowance for credit losses (4.3) (1.8) (1.3) (0.6) (0.8) (0.5) (9.3) Carrying Amount $ 1,104.2 $ 374.7 $ 343.5 $ 169.3 $ 355.6 $ 88.1 $ 2,435.4 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property Year Ended December 31, 2021 Prior to 2017 2017 2018 2019 2020 2021 Total (in millions of dollars) Internal Rating AA $ 3.3 $ — $ 24.0 $ — $ — $ — $ 27.3 A 414.6 68.0 71.1 28.9 17.6 110.6 710.8 BBB 561.2 227.3 283.3 331.9 163.1 242.6 1,809.4 BB 5.0 10.2 6.0 — — — 21.2 Total Amortized Cost 984.1 305.5 384.4 360.8 180.7 353.2 2,568.7 Allowance for credit losses (2.6) (1.4) (1.4) (1.4) (0.7) (0.8) (8.3) Carrying Amount $ 981.5 $ 304.1 $ 383.0 $ 359.4 $ 180.0 $ 352.4 $ 2,560.4 Loan-to-Value Ratio (1) <=65% $ 779.1 $ 146.9 $ 163.0 $ 80.7 $ 54.3 $ 124.7 $ 1,348.7 >65<=75% 115.7 115.4 215.4 280.1 126.4 228.5 1,081.5 >75%<=85% 89.3 26.3 — — — — 115.6 >85% — 16.9 6.0 — — — 22.9 Total Amortized Cost 984.1 305.5 384.4 360.8 180.7 353.2 2,568.7 Allowance for credit losses (2.6) (1.4) (1.4) (1.4) (0.7) (0.8) (8.3) Carrying Amount $ 981.5 $ 304.1 $ 383.0 $ 359.4 $ 180.0 $ 352.4 $ 2,560.4 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property The following tables present a roll forward of allowance for expected credit losses by loan-to-value ratio for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio (1) <=65% $ 2.6 $ 0.4 $ — $ — $ 3.0 >65<=75% 4.7 — — — 4.7 >75%<=85% 0.7 0.4 — — 1.1 >85% 0.3 0.2 — — 0.5 Total $ 8.3 $ 1.0 $ — $ — $ 9.3 Year Ended December 31, 2021 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio (1) <=65% $ 3.4 $ (0.8) $ — $ — $ 2.6 >65<=75% 7.3 (2.6) — — 4.7 >75%<=85% 1.3 (0.6) — — 0.7 >85% 1.1 (0.8) — — 0.3 Total $ 13.1 $ (4.8) $ — $ — $ 8.3 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property The increase in our estimate of expected losses during the year ended December 31, 2022 is primarily driven by heightened uncertainty surrounding the future macroeconomic outlook and reflects market conditions as of December 31, 2022. The decrease in our estimate of expected losses during the year ended December 31, 2021 is primarily due to improved economic conditions and recovery from COVID-19, especially as it relates to underlying commercial real estate values, and reflects market conditions at December 31, 2021. There were no troubled debt restructurings during 2022, 2021 or 2020. At December 31, 2022, we held no mortgage loans that were greater than 90 days past due regarding principal and/or interest payments. We had no loan foreclosures for the years ended December 31, 2022, 2021, or 2020. For the years ended December 31, 2022, 2021, and 2020 we had no impaired mortgage loans. We did not recognize any interest income during 2022, 2021 or 2020 on mortgage loans subsequent to impairment. For the years ended December 31, 2022 and 2021, we had commitments of $5.0 million and $26.3 million, respectively to fund certain commercial mortgage loans. Consistent with how we determine the estimate of current expected credit losses for our funded mortgage loans each period, we estimate expected credit losses for loans that have not been funded but we are committed to fund at the end of each period. For the year ended December 31, 2022, we had a nominal amount of expected credit losses related to unfunded commitments on our consolidated balance sheets. For the year ended December 31, 2021, we had $0.1 million of expected credit losses related to unfunded commitments on our consolidated balance sheets. Investment Real Estate Our investment real estate balance was $71.6 million and $119.5 million at December 31, 2022 and 2021, respectively, and the associated accumulated depreciation was $122.1 million and $171.3 million at December 31, 2022 and 2021, respectively. We did not recognize any impairments related to our real estate during 2022 or 2021. For the year ended December 31, 2020, we recognized $36.6 million in impairments related to certain of our real estate held for investment. During the first quarter of 2022, we reclassified one property previously held for the production of income to property held for sale. The carrying value of the property was $40.1 million and $40.9 million as of December 31, 2022 and December 31, 2021 , respectively, and is primarily recorded within our Corporate segment. The estimated fair value less cost to sell is above the carrying value of the property, and we expect to close the sale of the property in the first quarter of 2023. During the third quarter of 2022, we reclassified one property previously held for the production of income to property held for sale. The property had a carrying value of $0.8 million as of December 31, 2022 and December 31, 2021 , respectively, and is recorded within our Corporate segment. The estimated fair value less cost to sell is above the carrying value for this property, and we expect to close the sale of this property during 2023. During the third quarter of 2022 we reclassified one additional property previously held for the production of income to property held for sale. In November of 2022, we closed on the sale of this property. At the time of sale the carrying value of this property was $3.4 million, and we recognized a nominal realized gain. Transfers of Financial Assets To manage our cash position more efficiently, we may enter into repurchase agreements with unaffiliated financial institutions. We generally use repurchase agreements as a means to finance the purchase of invested assets or for short-term general business purposes until projected cash flows become available from our operations or existing investments. Our repurchase agreements are typically outstanding for less than 30 days. We post collateral through our repurchase agreement transactions whereby the counterparty commits to purchase securities with the agreement to resell them to us at a later, specified date. The fair value of collateral posted is generally 102 percent of the cash received. Our investment policy also permits us to lend fixed maturity securities to unaffiliated financial institutions in short-term securities lending agreements. These agreements increase our investment income with minimal risk. Our securities lending policy requires that a minimum of 102 percent of the fair value of the securities loaned be maintained as collateral. We may receive cash and/or securities as collateral under these agreements. Cash received as collateral is typically reinvested in short-term investments. If securities are received as collateral, we are not permitted to sell or re-post them. As of December 31, 2022, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $152.4 million, for which we received collateral in the form of cash and securities of $88.5 million and $69.8 million, respectively. As of December 31, 2021, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $283.7 million, for which we received collateral in the form of cash and securities of $94.8 million and $198.6 million, respectively. We had no outstanding repurchase agreements at December 31, 2022 or 2021. The remaining contractual maturities of our securities lending agreements disaggregated by class of collateral pledged are as follows: December 31 2022 2021 Overnight and Continuous (in millions of dollars) Borrowings United States Government and Government Agencies and Authorities $ 0.3 $ 0.1 State, Municipalities, and Political Subdivisions — 0.1 Public Utilities 6.3 3.1 All Other Corporate Bonds 81.9 91.5 Total Borrowings $ 88.5 $ 94.8 Gross Amount of Recognized Liability for Securities Lending Transactions 88.5 94.8 Amounts Related to Agreements Not Included in Offsetting Disclosure Contained Herein $ — $ — Certain of our U.S. insurance subsidiaries are members of regional FHLBs. Membership, which requires that we purchase a minimum amount of FHLB common stock on which we receive dividends, provides access to low-cost funding. Advances received from the FHLB are used for the purchase of fixed maturity securities. Additional common stock purchases may be required, based on the amount of funds we borrow from the FHLBs. The carrying value of common stock owned, collateral posted, and advances received are as follows: December 31 2022 2021 (in millions of dollars) Carrying Value of FHLB Common Stock $ 17.1 $ 22.1 Advances from FHLB 99.1 160.9 Carrying Value of Collateral Posted to FHLB Fixed Maturity Securities $ 527.1 $ 786.1 Commercial Mortgage Loans 801.9 930.0 Total Carrying Value of Collateral Posted to FHLB $ 1,329.0 $ 1,716.1 Offsetting of Financial Instruments We enter into master netting agreements with each of our derivative's counterparties. These agreements provide for conditional rights of set-off upon the occurrence of an early termination event. An early termination event is considered a default, and it allows the non-defaulting party to offset its contracts in a loss position against any gain positions or payments due to the defaulting party. Under our agreements, default type events are defined as failure to pay or deliver as contractually agreed, misrepresentation, bankruptcy, or merger without assumption. See Note 4 for further discussion of collateral related to our derivative contracts. We have securities lending agreements with unaffiliated financial institutions that post collateral to us in return for the use of our fixed maturity securities. A right of set-off exists that allows us to keep and apply collateral received in the event of default by the counterparty. Default within a securities lending agreement would typically occur if the counterparty failed to return the securities borrowed from us as contractually agreed. In addition, if we default by not returning collateral received, the counterparty has a right of set-off against our securities or any other amounts due to us. Shown below are our financial instruments that either meet the accounting requirements that allow them to be offset in our balance sheets or that are subject to an enforceable master netting arrangement or similar agreement. Our accounting policy is to not offset these financial instruments in our balance sheets. Net amounts disclosed below have been reduced by the amount of collateral pledged to or received from our counterparties. December 31, 2022 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 89.1 $ — $ 89.1 $ (38.0) $ (49.4) $ 1.7 Securities Lending 152.4 — 152.4 (63.9) (88.5) — Total $ 241.5 $ — $ 241.5 $ (101.9) $ (137.9) $ 1.7 Financial Liabilities: Derivatives $ 74.0 $ — $ 74.0 $ (73.2) $ — $ 0.8 Securities Lending 88.5 — 88.5 (88.5) — — Total $ 162.5 $ — $ 162.5 $ (161.7) $ — $ 0.8 December 31, 2021 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 39.5 $ — $ 39.5 $ (9.8) $ (28.4) $ 1.3 Securities Lending 283.7 — 283.7 (188.9) (94.8) — Total $ 323.2 $ — $ 323.2 $ (198.7) $ (123.2) $ 1.3 Financial Liabilities: Derivatives $ 35.0 $ — $ 35.0 $ (34.0) $ — $ 1.0 Securities Lending 94.8 — 94.8 (94.8) — — Total $ 129.8 $ — $ 129.8 $ (128.8) $ — $ 1.0 Net Investment Income Net investment income reported in our consolidated statements of income is presented below. Year Ended December 31 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities $ 1,849.8 $ 1,888.2 $ 2,164.0 Derivatives 57.8 68.6 78.7 Mortgage Loans 101.5 105.0 108.9 Policy Loans 20.0 19.7 20.0 Other Long-term Investments Perpetual Preferred Securities 1 5.0 6.9 (2.1) Private Equity Partnerships 2 110.1 165.4 19.8 Other 9.4 5.5 3.9 Short-term Investments 20.0 1.3 10.5 Gross Investment Income 2,173.6 2,260.6 2,403.7 Less Investment Expenses 39.4 35.1 30.6 Less Investment Income on Participation Fund Account Assets 12.0 12.3 12.4 Net Investment Income $ 2,122.2 $ 2,213.2 $ 2,360.7 1 The net unrealized gain (loss) recognized in net investment income for the year ended December 31, 2022 related to perpetual preferred securities still held at December 31, 2022 was $2.8 million. The net unrealized gain (loss) recognized in net investment income for the years ended December 31, 2021 and 2020 related to perpetual preferred securities still held at year-end was $4.4 million and $(4.6) million, respectively 2 Represents a net unrealized gain for the year ended December 31, 2022 related to private equity partnerships still held at December 31, 2022 of $124.1 million, reduced by net management fees and partnership expenses of $(14.0) million. For the years ended December 31, 2021 and 2020, the net unrealized gain related to private equity partnerships still held at year-end was $177.7 million and $29.1 million, respectively, reduced by net management fees and partnership expenses of $(12.3) million and $(9.3) million, respectively. See Note 2 for further discussion of private equity partnerships. Investment Gain and Loss Investment gains and losses are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities Gross Gains on Sales 1 $ 2.3 $ 76.2 $ 1,332.8 Gross Losses on Sales (28.8) (11.5) (20.3) Credit Losses (4.6) (9.3) (53.6) Mortgage Loans and Other Invested Assets Gross Gains on Sales 1.4 5.8 1.9 Gross Losses on Sales — — (0.3) Impairment Loss — — (36.6) Change in Allowance for Credit Losses (1.0) 4.7 (4.6) Embedded Derivative in Modified Coinsurance Arrangement 16.2 9.7 (17.0) All Other Derivatives 2.6 3.1 (2.5) Foreign Currency Transactions (3.8) (2.0) (0.7) Net Investment Gain (Loss) $ (15.7) $ 76.7 $ 1,199.1 1 Gross gains on sales of fixed maturity securities for the year ended December 31, 2021 includes gains of $67.6 million as a result of the second phase of the reinsurance transaction that we completed during the first quarter of 2021. Gross gains on sales of fixed maturity securities for the year ended December 31, 2020 includes gains of $1,302.3 million as a result of the first phase of the reinsurance transaction that we completed during the fourth quarter of 2020. See Note 12 for further discussion." id="sjs-B4">Fixed Maturity Securities At December 31, 2022 and 2021, all fixed maturity securities were classified as available-for-sale. The amortized cost and fair values of securities by security type are shown as follows: December 31, 2022 Amortized Cost, Gross of ACL (1) ACL (1) Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 503.8 $ — $ 20.3 $ 25.9 $ 498.2 States, Municipalities, and Political Subdivisions 4,006.0 — 87.1 635.9 3,457.2 Foreign Governments 908.1 — 34.9 115.9 827.1 Public Utilities 5,170.9 — 141.0 355.0 4,956.9 Mortgage/Asset-Backed Securities 592.1 — 8.2 27.0 573.3 All Other Corporate Bonds 26,640.3 — 452.1 2,567.8 24,524.6 Redeemable Preferred Stocks 4.0 — — 0.5 3.5 Total Fixed Maturity Securities $ 37,825.2 $ — $ 743.6 $ 3,728.0 $ 34,840.8 December 31, 2021 Amortized Cost, Gross of ACL (1) ACL (1) Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 460.1 $ — $ 120.1 $ 0.1 $ 580.1 States, Municipalities, and Political Subdivisions 4,150.2 — 584.2 6.9 4,727.5 Foreign Governments 952.0 — 215.3 20.7 1,146.6 Public Utilities 5,266.4 — 1,159.4 9.8 6,416.0 Mortgage/Asset-Backed Securities 587.9 — 50.4 — 638.3 All Other Corporate Bonds 25,966.1 — 3,919.9 62.6 29,823.4 Redeemable Preferred Stocks 4.0 — 0.1 — 4.1 Total Fixed Maturity Securities $ 37,386.7 $ — $ 6,049.4 $ 100.1 $ 43,336.0 (1) Allowance for Credit Losses The following charts indicate the length of time our fixed maturity securities have been in a gross unrealized loss position. December 31, 2022 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 246.6 $ 22.6 $ 12.2 $ 3.3 States, Municipalities, and Political Subdivisions 1,920.1 476.1 346.6 159.8 Foreign Governments 160.1 47.9 176.9 68.0 Public Utilities 2,242.2 252.0 255.2 103.0 Mortgage/Asset-Backed Securities 386.6 27.0 0.1 — All Other Corporate Bonds 15,865.6 1,799.7 2,194.1 768.1 Redeemable Preferred Stocks 3.5 0.5 — — Total Fixed Maturity Securities $ 20,824.7 $ 2,625.8 $ 2,985.1 $ 1,102.2 December 31, 2021 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 9.3 $ 0.1 $ — $ — States, Municipalities, and Political Subdivisions 326.4 6.9 0.4 — Foreign Governments 234.4 18.9 10.7 1.8 Public Utilities 263.3 9.1 17.6 0.7 Mortgage/Asset-Backed Securities 29.2 — 0.1 — All Other Corporate Bonds 2,146.3 51.6 199.4 11.0 Total Fixed Maturity Securities $ 3,008.9 $ 86.6 $ 228.2 $ 13.5 The following is a distribution of the maturity dates for fixed maturity securities. The maturity dates have not been adjusted for possible calls or prepayments. December 31, 2022 Amortized Cost, Net of ACL (1) Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 1,133.5 $ 2.9 $ 339.1 $ 5.7 $ 791.6 Over 1 year through 5 years 7,090.8 86.7 1,953.2 238.4 4,985.9 Over 5 years through 10 years 10,096.7 294.8 3,538.9 863.8 5,988.8 Over 10 years 18,912.1 351.0 5,013.2 2,593.1 11,656.8 37,233.1 735.4 10,844.4 3,701.0 23,423.1 Mortgage/Asset-Backed Securities 592.1 8.2 186.6 27.0 386.7 Total Fixed Maturity Securities $ 37,825.2 $ 743.6 $ 11,031.0 $ 3,728.0 $ 23,809.8 December 31, 2021 Amortized Cost, Net of ACL (1) Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 767.3 $ 17.6 $ 756.0 $ 0.1 $ 28.9 Over 1 year through 5 years 6,613.2 540.2 7,050.5 6.0 96.9 Over 5 years through 10 years 10,614.3 1,453.3 10,905.0 26.0 1,136.6 Over 10 years 18,804.0 3,987.9 20,778.4 68.0 1,945.4 36,798.8 5,999.0 39,489.9 100.1 3,207.8 Mortgage/Asset-Backed Securities 587.9 50.4 609.0 — 29.3 Total Fixed Maturity Securities $ 37,386.7 $ 6,049.4 $ 40,098.9 $ 100.1 $ 3,237.1 (1) Allowance for Credit Losses The following chart depicts an analysis of our fixed maturity security portfolio between investment-grade and below-investment-grade categories as of December 31, 2022: Gross Unrealized Loss Fair Value Gross Unrealized Gain Amount Percent of Total Gross Unrealized Loss (in millions of dollars) Investment-Grade $ 32,851.0 $ 734.6 $ 3,545.5 95.1 % Below-Investment-Grade 1,989.8 9.0 182.5 4.9 Total Fixed Maturity Securities $ 34,840.8 $ 743.6 $ 3,728.0 100.0 % The unrealized losses on investment-grade fixed maturity securities principally relate to changes in interest rates or changes in market or sector credit spreads which occurred subsequent to the acquisition of the securities. Below-investment-grade fixed maturity securities are generally more likely to develop credit concerns than investment-grade securities. At December 31, 2022, the unrealized losses in our below-investment-grade fixed maturity securities were generally due to credit spreads in certain industries or sectors and, to a lesser extent, credit concerns related to specific securities. For each specific security in an unrealized loss position, we believe that there are positive factors which mitigate credit concerns and that the securities for which we have not recorded a credit loss will recover in value. We have the ability and intent to continue to hold these securities to recovery of amortized cost and believe that no credit losses have occurred. As of December 31, 2022, we held 882 individual investment-grade fixed maturity securities and 112 individual below-investment-grade fixed maturity securities that were in an unrealized loss position, of which 262 investment-grade fixed maturity securities and 16 below-investment-grade fixed maturity securities had been in an unrealized loss position continuously for over one year. In determining when a decline in fair value below amortized cost of a fixed maturity security represents a credit loss, we evaluate the following factors: • Whether we expect to recover the entire amortized cost basis of the security • Whether we intend to sell the security or will be required to sell the security before the recovery of its amortized cost basis • Whether the security is current as to principal and interest payments • The significance of the decline in value • Current and future business prospects and trends of earnings • The valuation of the security's underlying collateral • Relevant industry conditions and trends relative to their historical cycles • Market conditions • Rating agency and governmental actions • Bid and offering prices and the level of trading activity • Adverse changes in estimated cash flows for securitized investments • Changes in fair value subsequent to the balance sheet date • Any other key measures for the related security While determining whether a credit loss exists is a judgmental area, we utilize a formal, well-defined, and disciplined process to monitor and evaluate our fixed income investment portfolio, supported by issuer specific research and documentation as of the end of each period. The process results in a thorough evaluation of problem investments and the recording of credit losses on a timely basis for investments determined to have a credit loss. We calculate the allowance for credit losses of fixed maturity securities based on the present value of our best estimate of cash flows expected to be collected, discounted using the effective interest rate implicit in the security at the date of acquisition. When estimating future cash flows, we analyze the strength of the issuer’s balance sheet, its debt obligations and near-term funding arrangements, cash flow and liquidity, the profitability of its core businesses, the availability of marketable assets which could be sold to increase liquidity, its industry fundamentals and regulatory environment, and its access to capital markets. The following tables present a rollforward of the allowance for credit losses on available-for-sale fixed maturity securities, which were classified as "public utilities" during year ended December 31, 2022 and "all other corporate bonds" during the year ended December 31, 2021, respectively. Year Ended December 31 2022 2021 (in millions of dollars) Balance, beginning of period $ — $ 6.8 Credit losses on securities for which credit losses were not previously recorded 4.6 — Change in allowance on securities with allowance recorded in previous period — 0.5 Change in allowance on securities disposed during the period (4.6) (7.3) Balance, end of period $ — $ — In the fourth quarter of 2022, the issuer of a fixed maturity security previously classified as "public utilities" entered into a troubled debt restructuring agreement. In order to maximize recovery of the investment, the debt was restructured by way of principal reduction, interest forgiveness, and a debt to equity conversion. Principal owed was reduced by $4.8 million, semi-annual interest payments for the period beginning June 30, 2022 and ending June 30, 2024 were forgiven, and a portion of the remaining debt was converted to equity. As of December 31, 2022, we have received $4.9 million of an equity stake in the restructured entity, and have recorded receivables for $5.2 million and $2.8 million in cash to be received by March 31, 2023 and December 31, 2023, respectively. The amortized cost of the fixed maturity security prior to the restructuring was $17.7 million, and the restructuring resulted in a total loss of $4.8 million, which was recognized during 2022. At December 31, 2022, we had commitments of $58.7 million to fund private placement fixed maturity securities, the amount of which may or may not be funded. Variable Interest Entities We invest in variable interests issued by variable interest entities. These investments, which are passive in nature, include minority ownership interests in private equity partnerships, tax credit partnerships, and special purpose entities. For those variable interests that are not consolidated in our financial statements, we are not the primary beneficiary because we have neither the power to direct the activities that are most significant to economic performance nor the responsibility to absorb a majority of the expected losses. The determination of whether we are the primary beneficiary is performed at the time of our initial investment and at the date of each subsequent reporting period. As of December 31, 2022, the carrying amount of our variable interest entity investments that are not consolidated in our financial statements was $1,195.3 million, comprised of $1.0 million of tax credit partnerships and $1,194.3 million of private equity partnerships. At December 31, 2021, the carrying amount of our variable interest entity investments that are not consolidated in our financial statements was $987.9 million, comprised of $9.3 million of tax credit partnerships and $978.6 million of private equity partnerships. These variable interest entity investments are reported as other long-term investments in our consolidated balance sheets. The Company invests in tax credit partnerships primarily for the receipt of income tax credits and tax benefits derived from passive losses on the investments. Amounts recognized in the consolidated statements of income are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Income Tax Credits $ 8.0 $ 21.6 $ 33.2 Amortization, Net of Tax (5.9) (15.0) (21.9) Income Tax Benefit $ 2.1 $ 6.6 $ 11.3 Contractually, we are a limited partner in these tax credit partnerships, and our maximum exposure to loss is limited to the carrying value of our investment, which includes $0.7 million of unfunded unconditional commitments at December 31, 2022. See Note 2 for commitments to fund private equity partnerships. Mortgage Loans Our mortgage loan portfolio is well diversified by both geographic region and property type to reduce risk of concentration. All of our mortgage loans are collateralized by commercial real estate. When issuing a new loan, our general policy is not to exceed a loan-to-value ratio, or the ratio of the loan balance to the estimated fair value of the underlying collateral, of 75 percent. We update the loan-to-value ratios at least every three years for each loan, and properties undergo a general inspection at least every two years. Our general policy for newly issued loans is to have a debt service coverage ratio greater than 1.25 times on a normalized 25 year amortization period. We update our debt service coverage ratios annually. We carry our mortgage loans at amortized cost less the allowance for expected credit losses. The amortized cost of our mortgage loans was $2,444.7 million and $2,568.7 million at December 31, 2022 and 2021, respectively. The allowance for expected credit losses was $9.3 million and $8.3 million at December 31, 2022 and 2021, respectively. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. We report accrued interest income for our mortgage loans as accrued investment income on our consolidated balance sheets, and the amount of the accrued income was $7.7 million and $8.1 million at December 31, 2022 and 2021, respectively. The carrying amount of mortgage loans by property type and geographic region are presented below. December 31 2022 2021 (in millions of dollars) Carrying Percent of Carrying Percent of Amount Total Amount Total Property Type Apartment $ 688.6 28.3 % $ 780.0 30.5 % Industrial 745.3 30.6 734.4 28.7 Office 423.0 17.4 467.2 18.2 Retail 534.5 21.9 533.3 20.8 Other 44.0 1.8 45.5 1.8 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % Region New England $ 52.4 2.2 % $ 54.9 2.1 % Mid-Atlantic 192.4 7.9 214.7 8.4 East North Central 313.0 12.9 298.4 11.7 West North Central 181.4 7.4 193.1 7.5 South Atlantic 539.3 22.1 582.1 22.7 East South Central 101.8 4.2 120.7 4.7 West South Central 212.6 8.7 243.2 9.6 Mountain 298.7 12.3 290.6 11.3 Pacific 543.8 22.3 562.7 22.0 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % The risk in our mortgage loan portfolio is primarily related to vacancy rates. Events or developments, such as economic conditions that impact the ability of the borrowers to ensure occupancy of the property, may have a negative effect on our mortgage loan portfolio, particularly to the extent that our portfolio is concentrated in an affected region or property type. An increase in vacancies increases the probability of default, which would negatively affect our expected losses in our mortgage loan portfolio. We evaluate each of our mortgage loans individually for impairment and assign an internal credit quality rating based on a comprehensive rating system used to evaluate the credit risk of the loan. The factors we use to derive our internal credit ratings may include the following: • Loan-to-value ratio based on internal appraisal of property • Debt service coverage ratio based on current operating income • Property location, including regional economics, trends, and demographics • Age, condition, and construction quality of property • Current and historical occupancy of property • Lease terms relative to market • Tenant size and financial strength • Borrower's financial strength • Borrower's equity in transaction • Additional collateral, if any Although all available and applicable factors are considered in our analysis, loan-to-value and debt service coverage ratios are the most critical factors in determining whether we will initially issue the loan and also in assigning values and determining impairment. We assign an overall rating to each loan using an internal rating scale of AA (highest quality) to B (lowest quality). We review and adjust, as needed, our internal credit quality ratings on an annual basis. This review process is performed more frequently for mortgage loans deemed to have a higher risk of delinquency. The following tables present information about mortgage loans by the applicable credit quality indicators: December 31 2022 2021 (in millions of dollars) Carrying Amount Percent of Total Carrying Amount Percent of Total Internal Rating AA $ 92.3 3.8 % $ 27.3 1.1 % A 843.9 34.6 709.6 27.7 BBB 1,458.0 59.9 1,802.6 70.4 BB 41.2 1.7 20.9 0.8 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % Loan-to-Value Ratio (1) <= 65% $ 1,389.6 57.0 % $ 1,346.1 52.6 % > 65% <= 75% 937.2 38.5 1,076.8 42.0 > 75% <= 85% 75.0 3.1 114.9 4.5 > 85% 33.6 1.4 22.6 0.9 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property The following table presents the amortized cost of our mortgage loans by year of origination and credit quality indicators for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 Prior to 2018 2018 2019 2020 2021 2022 Total (in millions of dollars) Internal Rating AA $ 53.8 $ 27.5 $ 11.1 $ — $ — $ — $ 92.4 A 485.0 123.3 96.8 35.9 80.6 24.0 845.6 BBB 534.0 219.8 236.9 134.0 275.8 64.6 1,465.1 BB 35.7 5.9 — — — — 41.6 Total Amortized Cost 1,108.5 376.5 344.8 169.9 356.4 88.6 2,444.7 Allowance for credit losses (4.3) (1.8) (1.3) (0.6) (0.8) (0.5) (9.3) Carrying Amount $ 1,104.2 $ 374.7 $ 343.5 $ 169.3 $ 355.6 $ 88.1 $ 2,435.4 Loan-to-Value Ratio (1) <=65% $ 782.6 $ 189.0 $ 193.9 $ 81.3 $ 128.9 $ 16.9 $ 1,392.6 >65<=75% 230.2 181.6 150.9 80.1 227.5 71.7 942.0 >75%<=85% 67.5 — — 8.5 — — 76.0 >85% 28.2 5.9 — — — — 34.1 Total Amortized Cost 1,108.5 376.5 344.8 169.9 356.4 88.6 2,444.7 Allowance for credit losses (4.3) (1.8) (1.3) (0.6) (0.8) (0.5) (9.3) Carrying Amount $ 1,104.2 $ 374.7 $ 343.5 $ 169.3 $ 355.6 $ 88.1 $ 2,435.4 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property Year Ended December 31, 2021 Prior to 2017 2017 2018 2019 2020 2021 Total (in millions of dollars) Internal Rating AA $ 3.3 $ — $ 24.0 $ — $ — $ — $ 27.3 A 414.6 68.0 71.1 28.9 17.6 110.6 710.8 BBB 561.2 227.3 283.3 331.9 163.1 242.6 1,809.4 BB 5.0 10.2 6.0 — — — 21.2 Total Amortized Cost 984.1 305.5 384.4 360.8 180.7 353.2 2,568.7 Allowance for credit losses (2.6) (1.4) (1.4) (1.4) (0.7) (0.8) (8.3) Carrying Amount $ 981.5 $ 304.1 $ 383.0 $ 359.4 $ 180.0 $ 352.4 $ 2,560.4 Loan-to-Value Ratio (1) <=65% $ 779.1 $ 146.9 $ 163.0 $ 80.7 $ 54.3 $ 124.7 $ 1,348.7 >65<=75% 115.7 115.4 215.4 280.1 126.4 228.5 1,081.5 >75%<=85% 89.3 26.3 — — — — 115.6 >85% — 16.9 6.0 — — — 22.9 Total Amortized Cost 984.1 305.5 384.4 360.8 180.7 353.2 2,568.7 Allowance for credit losses (2.6) (1.4) (1.4) (1.4) (0.7) (0.8) (8.3) Carrying Amount $ 981.5 $ 304.1 $ 383.0 $ 359.4 $ 180.0 $ 352.4 $ 2,560.4 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property The following tables present a roll forward of allowance for expected credit losses by loan-to-value ratio for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio (1) <=65% $ 2.6 $ 0.4 $ — $ — $ 3.0 >65<=75% 4.7 — — — 4.7 >75%<=85% 0.7 0.4 — — 1.1 >85% 0.3 0.2 — — 0.5 Total $ 8.3 $ 1.0 $ — $ — $ 9.3 Year Ended December 31, 2021 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio (1) <=65% $ 3.4 $ (0.8) $ — $ — $ 2.6 >65<=75% 7.3 (2.6) — — 4.7 >75%<=85% 1.3 (0.6) — — 0.7 >85% 1.1 (0.8) — — 0.3 Total $ 13.1 $ (4.8) $ — $ — $ 8.3 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property The increase in our estimate of expected losses during the year ended December 31, 2022 is primarily driven by heightened uncertainty surrounding the future macroeconomic outlook and reflects market conditions as of December 31, 2022. The decrease in our estimate of expected losses during the year ended December 31, 2021 is primarily due to improved economic conditions and recovery from COVID-19, especially as it relates to underlying commercial real estate values, and reflects market conditions at December 31, 2021. There were no troubled debt restructurings during 2022, 2021 or 2020. At December 31, 2022, we held no mortgage loans that were greater than 90 days past due regarding principal and/or interest payments. We had no loan foreclosures for the years ended December 31, 2022, 2021, or 2020. For the years ended December 31, 2022, 2021, and 2020 we had no impaired mortgage loans. We did not recognize any interest income during 2022, 2021 or 2020 on mortgage loans subsequent to impairment. For the years ended December 31, 2022 and 2021, we had commitments of $5.0 million and $26.3 million, respectively to fund certain commercial mortgage loans. Consistent with how we determine the estimate of current expected credit losses for our funded mortgage loans each period, we estimate expected credit losses for loans that have not been funded but we are committed to fund at the end of each period. For the year ended December 31, 2022, we had a nominal amount of expected credit losses related to unfunded commitments on our consolidated balance sheets. For the year ended December 31, 2021, we had $0.1 million of expected credit losses related to unfunded commitments on our consolidated balance sheets. Investment Real Estate Our investment real estate balance was $71.6 million and $119.5 million at December 31, 2022 and 2021, respectively, and the associated accumulated depreciation was $122.1 million and $171.3 million at December 31, 2022 and 2021, respectively. We did not recognize any impairments related to our real estate during 2022 or 2021. For the year ended December 31, 2020, we recognized $36.6 million in impairments related to certain of our real estate held for investment. During the first quarter of 2022, we reclassified one property previously held for the production of income to property held for sale. The carrying value of the property was $40.1 million and $40.9 million as of December 31, 2022 and December 31, 2021 , respectively, and is primarily recorded within our Corporate segment. The estimated fair value less cost to sell is above the carrying value of the property, and we expect to close the sale of the property in the first quarter of 2023. During the third quarter of 2022, we reclassified one property previously held for the production of income to property held for sale. The property had a carrying value of $0.8 million as of December 31, 2022 and December 31, 2021 , respectively, and is recorded within our Corporate segment. The estimated fair value less cost to sell is above the carrying value for this property, and we expect to close the sale of this property during 2023. During the third quarter of 2022 we reclassified one additional property previously held for the production of income to property held for sale. In November of 2022, we closed on the sale of this property. At the time of sale the carrying value of this property was $3.4 million, and we recognized a nominal realized gain. Transfers of Financial Assets To manage our cash position more efficiently, we may enter into repurchase agreements with unaffiliated financial institutions. We generally use repurchase agreements as a means to finance the purchase of invested assets or for short-term general business purposes until projected cash flows become available from our operations or existing investments. Our repurchase agreements are typically outstanding for less than 30 days. We post collateral through our repurchase agreement transactions whereby the counterparty commits to purchase securities with the agreement to resell them to us at a later, specified date. The fair value of collateral posted is generally 102 percent of the cash received. Our investment policy also permits us to lend fixed maturity securities to unaffiliated financial institutions in short-term securities lending agreements. These agreements increase our investment income with minimal risk. Our securities lending policy requires that a minimum of 102 percent of the fair value of the securities loaned be maintained as collateral. We may receive cash and/or securities as collateral under these agreements. Cash received as collateral is typically reinvested in short-term investments. If securities are received as collateral, we are not permitted to sell or re-post them. As of December 31, 2022, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $152.4 million, for which we received collateral in the form of cash and securities of $88.5 million and $69.8 million, respectively. As of December 31, 2021, the carrying amount of fixed maturity securities loaned to third parties under our securities lending program was $283.7 million, for which we received collateral in the form of cash and securities of $94.8 million and $198.6 million, respectively. We had no outstanding repurchase agreements at December 31, 2022 or 2021. The remaining contractual maturities of our securities lending agreements disaggregated by class of collateral pledged are as follows: December 31 2022 2021 Overnight and Continuous (in millions of dollars) Borrowings United States Government and Government Agencies and Authorities $ 0.3 $ 0.1 State, Municipalities, and Political Subdivisions — 0.1 Public Utilities 6.3 3.1 All Other Corporate Bonds 81.9 91.5 Total Borrowings $ 88.5 $ 94.8 Gross Amount of Recognized Liability for Securities Lending Transactions 88.5 94.8 Amounts Related to Agreements Not Included in Offsetting Disclosure Contained Herein $ — $ — Certain of our U.S. insurance subsidiaries are members of regional FHLBs. Membership, which requires that we purchase a minimum amount of FHLB common stock on which we receive dividends, provides access to low-cost funding. Advances received from the FHLB are used for the purchase of fixed maturity securities. Additional common stock purchases may be required, based on the amount of funds we borrow from the FHLBs. The carrying value of common stock owned, collateral posted, and advances received are as follows: December 31 2022 2021 (in millions of dollars) Carrying Value of FHLB Common Stock $ 17.1 $ 22.1 Advances from FHLB 99.1 160.9 Carrying Value of Collateral Posted to FHLB Fixed Maturity Securities $ 527.1 $ 786.1 Commercial Mortgage Loans 801.9 930.0 Total Carrying Value of Collateral Posted to FHLB $ 1,329.0 $ 1,716.1 Offsetting of Financial Instruments We enter into master netting agreements with each of our derivative's counterparties. These agreements provide for conditional rights of set-off upon the occurrence of an early termination event. An early termination event is considered a default, and it allows the non-defaulting party to offset its contracts in a loss position against any gain positions or payments due to the defaulting party. Under our agreements, default type events are defined as failure to pay or deliver as contractually agreed, misrepresentation, bankruptcy, or merger without assumption. See Note 4 for further discussion of collateral related to our derivative contracts. We have securities lending agreements with unaffiliated financial institutions that post collateral to us in return for the use of our fixed maturity securities. A right of set-off exists that allows us to keep and apply collateral received in the event of default by the counterparty. Default within a securities lending agreement would typically occur if the counterparty failed to return the securities borrowed from us as contractually agreed. In addition, if we default by not returning collateral received, the counterparty has a right of set-off against our securities or any other amounts due to us. Shown below are our financial instruments that either meet the accounting requirements that allow them to be offset in our balance sheets or that are subject to an enforceable master netting arrangement or similar agreement. Our accounting policy is to not offset these financial instruments in our balance sheets. Net amounts disclosed below have been reduced by the amount of collateral pledged to or received from our counterparties. December 31, 2022 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 89.1 $ — $ 89.1 $ (38.0) $ (49.4) $ 1.7 Securities Lending 152.4 — 152.4 (63.9) (88.5) — Total $ 241.5 $ — $ 241.5 $ (101.9) $ (137.9) $ 1.7 Financial Liabilities: Derivatives $ 74.0 $ — $ 74.0 $ (73.2) $ — $ 0.8 Securities Lending 88.5 — 88.5 (88.5) — — Total $ 162.5 $ — $ 162.5 $ (161.7) $ — $ 0.8 December 31, 2021 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 39.5 $ — $ 39.5 $ (9.8) $ (28.4) $ 1.3 Securities Lending 283.7 — 283.7 (188.9) (94.8) — Total $ 323.2 $ — $ 323.2 $ (198.7) $ (123.2) $ 1.3 Financial Liabilities: Derivatives $ 35.0 $ — $ 35.0 $ (34.0) $ — $ 1.0 Securities Lending 94.8 — 94.8 (94.8) — — Total $ 129.8 $ — $ 129.8 $ (128.8) $ — $ 1.0 Net Investment Income Net investment income reported in our consolidated statements of income is presented below. Year Ended December 31 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities $ 1,849.8 $ 1,888.2 $ 2,164.0 Derivatives 57.8 68.6 78.7 Mortgage Loans 101.5 105.0 108.9 Policy Loans 20.0 19.7 20.0 Other Long-term Investments Perpetual Preferred Securities 1 5.0 6.9 (2.1) Private Equity Partnerships 2 110.1 165.4 19.8 Other 9.4 5.5 3.9 Short-term Investments 20.0 1.3 10.5 Gross Investment Income 2,173.6 2,260.6 2,403.7 Less Investment Expenses 39.4 35.1 30.6 Less Investment Income on Participation Fund Account Assets 12.0 12.3 12.4 Net Investment Income $ 2,122.2 $ 2,213.2 $ 2,360.7 1 The net unrealized gain (loss) recognized in net investment income for the year ended December 31, 2022 related to perpetual preferred securities still held at December 31, 2022 was $2.8 million. The net unrealized gain (loss) recognized in net investment income for the years ended December 31, 2021 and 2020 related to perpetual preferred securities still held at year-end was $4.4 million and $(4.6) million, respectively 2 Represents a net unrealized gain for the year ended December 31, 2022 related to private equity partnerships still held at December 31, 2022 of $124.1 million, reduced by net management fees and partnership expenses of $(14.0) million. For the years ended December 31, 2021 and 2020, the net unrealized gain related to private equity partnerships still held at year-end was $177.7 million and $29.1 million, respectively, reduced by net management fees and partnership expenses of $(12.3) million and $(9.3) million, respectively. See Note 2 for further discussion of private equity partnerships. Investment Gain and Loss Investment gains and losses are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities Gross Gains on Sales 1 $ 2.3 $ 76.2 $ 1,332.8 Gross Losses on Sales (28.8) (11.5) (20.3) Credit Losses (4.6) (9.3) (53.6) Mortgage Loans and Other Invested Assets Gross Gains on Sales 1.4 5.8 1.9 Gross Losses on Sales — — (0.3) Impairment Loss — — (36.6) Change in Allowance for Credit Losses (1.0) 4.7 (4.6) Embedded Derivative in Modified Coinsurance Arrangement 16.2 9.7 (17.0) All Other Derivatives 2.6 3.1 (2.5) Foreign Currency Transactions (3.8) (2.0) (0.7) Net Investment Gain (Loss) $ (15.7) $ 76.7 $ 1,199.1 1 Gross gains on sales of fixed maturity securities for the year ended December 31, 2021 includes gains of $67.6 million as a result of the second phase of the reinsurance transaction that we completed during the first quarter of 2021. Gross gains on sales of fixed maturity securities for the year ended December 31, 2020 includes gains of $1,302.3 million as a result of the first phase of the reinsurance transaction that we completed during the fourth quarter of 2020. See Note 12 for further discussion.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Purpose of Derivatives We are exposed to certain risks relating to our ongoing business operations. The primary risks managed by using derivative instruments are interest rate risk, risk related to matching duration for our assets and liabilities, foreign currency risk, credit risk, and equity risk. Historically, we have utilized current and forward interest rate swaps, current and forward currency swaps, forward benchmark interest rate locks, currency forward contracts, forward contracts on specific fixed income securities, credit default swaps, and total return swaps. Transactions hedging interest rate risk are primarily associated with our individual and group long-term care and individual and group disability products. All other product portfolios are periodically reviewed to determine if hedging strategies would be appropriate for risk management purposes. We do not use derivative financial instruments for speculative purposes. Derivatives designated as cash flow hedges and used to reduce our exposure to interest rate and duration risk are as follows: • Interest rate swaps were used to hedge interest rate risks and to improve the matching of assets and liabilities. An interest rate swap is an agreement in which we agree with other parties to exchange, at specified intervals, the difference between fixed rate and variable rate interest amounts. We used interest rate swaps to hedge the anticipated purchase of fixed maturity securities thereby protecting us from the potential adverse impact of declining interest rates on the associated policy reserves. We also used interest rate swaps to hedge the potential adverse impact of rising interest rates in anticipation of issuing fixed rate long-term debt. • Forward benchmark interest rate locks are used to minimize interest rate risk associated with the anticipated purchase or disposal of fixed maturity securities or the anticipated issuance of fixed rate long term debt. A forward benchmark interest rate lock is a derivative contract without an initial investment where we and the counterparty agree to purchase or sell a specific benchmark interest rate fixed maturity bond at a future date at a pre-determined price or yield. Derivatives designated as fair value hedges and previously used to reduce our exposure to interest rate and duration risk included: • Interest rate swaps were used to effectively convert certain fixed rate, long-term debt into floating rate long-term debt. Under these swap agreements, we received a fixed rate of interest and paid a variable rate of interest. Derivatives designated as either cash flow or fair value hedges and used to reduce our exposure to foreign currency risk are as follows: • Foreign currency interest rate swaps are used to hedge the currency risk of certain foreign currency-denominated fixed maturity securities owned for portfolio diversification. Under these swap agreements, we agree to pay, at specified intervals, fixed rate foreign currency-denominated principal and interest payments in exchange for fixed rate payments in the functional currency of the operating segment. Derivatives not designated as hedging instruments and used to reduce our exposure to foreign currency risk, credit losses on securities owned, and volatility of the underlying deferred assets in our non-qualified defined contribution plan are as follows: • Foreign currency interest rate swaps previously designated as hedges were used to hedge the currency risk of certain foreign currency-denominated fixed maturity securities owned for portfolio diversification. These derivatives were effective hedges prior to novation to a new counterparty. In conjunction with the novation, these derivatives were de-designated as hedges. We agree to pay, at specified intervals, fixed rate foreign currency-denominated principal and interest payments in exchange for fixed rate payments in the functional currency of the operating segment. We hold offsetting swaps wherein we agree to pay fixed rate principal and interest payments in the functional currency of the operating segment in exchange for fixed rate foreign currency-denominated payments. • Credit default swaps were used as economic hedges against credit risk but do not qualify for hedge accounting. A credit default swap is an agreement in which we agree with another party to pay, at specified intervals, a fixed-rate fee in exchange for insurance against a credit event on a specific investment. If a defined credit event occurred, our counterparty could have either paid us a net cash settlement, or we could have surrendered the specific investment to them in exchange for cash equal to the full notional amount of the swap. Credit events typically include events such as bankruptcy, failure to pay, or certain types of debt restructuring. • Foreign currency forward contracts are used to minimize foreign currency risk. A foreign currency forward is a derivative without an initial investment where we and the counterparty agree to exchange a specific amount of currencies, at a specific exchange rate, on a specific date. We use these forward contracts to hedge the currency risk arising from foreign-currency denominated investments. • Total Return Swaps are used to economically hedge a portion of the liability related to our non-qualified defined contribution plan. A total return swap is an agreement in which we pay a floating rate of interest to the counterparty and receive the total return on a portfolio of exchange traded funds. These swaps are cash settled on the last day of every month and the notional is re-established each month based on periodic distributions from and contributions to the plan assets. Derivative Risks The basic types of risks associated with derivatives are market risk (that the value of the derivative will be adversely impacted by changes in the market, primarily the change in interest and exchange rates) and credit risk (that the counterparty will not perform according to the terms of the contract). The market risk of the derivatives should generally offset the market risk associated with the hedged financial instrument or liability. To help limit the credit exposure of the derivatives, we enter into master netting agreements with our counterparties whereby contracts in a gain position can be offset against contracts in a loss position. We also typically enter into bilateral, cross-collateralization agreements with our counterparties to help limit the credit exposure of the derivatives. These agreements require the counterparty in a loss position to submit acceptable collateral with the other counterparty in the event the net loss position meets or exceeds an agreed upon amount. Credit exposure on derivatives is limited to the value of those contracts in a net gain position, including accrued interest receivable less collateral held. At December 31, 2022 and 2021, we had $1.7 million and $1.3 million credit exposure on derivatives, respectively. The table below summarizes the nature and amount of collateral received from and posted to our derivative counterparties. December 31 2022 2021 (in millions of dollars) Carrying Value of Collateral Received from Counterparties Cash $ 49.4 $ 32.0 Carrying Value of Collateral Posted to Counterparties Cash $ 5.1 $ — Fixed Maturity Securities 39.6 27.6 $ 44.7 $ 27.6 See Note 3 for further discussion of our master netting agreements. The majority of our derivative instruments contain provisions that require us to maintain specified issuer credit ratings and financial strength ratings. Should our ratings fall below these specified levels, we would be in violation of the provisions, and our derivatives counterparties could terminate our contracts and request immediate payment. The aggregate fair value of all derivative instruments with credit risk-related contingent features that were in a liability position was $74.0 million and $35.0 million at December 31, 2022 and 2021, respectively. Cash Flow Hedges As of December 31, 2022 and 2021, we had $168.9 million and $181.3 million, respectively, notional amount of receive fixed, pay fixed, open current and forward foreign currency interest rate swaps to hedge fixed income foreign currency-denominated securities. During 2022 we entered into $779.0 million of notional forward benchmark interest rate locks in order to hedge the anticipated purchase of fixed maturity securities. As of December 31, 2022, we had $764.0 million notional amount of forward benchmark interest rate locks. During 2021, we entered into a $250.0 million notional forward benchmark interest rate lock in order to hedge the interest rate risk associated with the cash flows related to the early redemption of certain of our debt securities. We terminated the interest rate lock in 2021 and recognized a loss of $1.2 million that was reported as a cost related to the early retirement of debt in our income statement. During the fourth quarter of 2020 and the first quarter of 2021, in connection with the Closed Block individual disability reinsurance transaction, we reclassified $30.7 million and $0.6 million, respectively, of deferred gains from accumulated other comprehensive income into earnings included in the net investment gain (loss) line item on our income statement. The deferred gains were related to previously terminated interest rate swaps designated as hedging instruments of fixed maturity securities in the Closed Block individual disability product line. See Note 12 for further discussion. As of December 31, 2022, we expect to amortize approximately $35.4 million of net deferred gains on derivative instruments during the next twelve months. This amount will be reclassified from accumulated other comprehensive income into earnings and reported on the same income statement line item as the hedged item. The income statement line items that will be affected by this amortization are net investment income and interest and debt expense. Additional amounts that may be reclassified from accumulated other comprehensive income into earnings to offset the earnings impact of foreign currency translation of hedged items are not estimable. As of December 31, 2022, we are hedging the variability of future cash flows associated with forecasted transactions through the year 2052. Fair Value Hedges As of December 31, 2022 and 2021, we had $557.8 million and $498.5 million notional amount of receive fixed, pay fixed, open current and forward foreign currency interest rate swaps to hedge fixed income foreign currency-denominated securities. The following table summarizes the carrying amount of hedged assets and the related cumulative basis adjustments related to our fair value hedges: Carrying Amount of Hedged Assets Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets December 31, 2022 December 31, 2021 December 31, 2022 December 31, 2021 (in millions of dollars) Fixed maturity securities: Receive fixed functional currency interest, pay fixed foreign currency interest $ 394.4 $ 466.3 $ (24.8) $ 2.0 For the years ended December 31, 2022, 2021, and 2020, $17.6 million, $16.6 million, and $(1.8) million, respectively, of the derivative instruments' gain (loss) was excluded from the assessment of hedge effectiveness. There were no instances wherein we discontinued fair value hedge accounting due to a hedged firm commitment no longer qualifying as a fair value hedge. Derivatives not Designated as Hedging Instruments As of December 31, 2022 and 2021, we held $132.0 million and $148.2 million, respectively, notional amount of receive fixed, pay fixed, foreign currency interest rate swaps. These derivatives are not designated as hedges, and as such, changes in fair value related to these derivatives are reported in earnings as a component of net investment gain or loss. As of December 31, 2022, we held no single name credit default swaps. As of December 31, 2021, we held $11.6 million, respectively, notional amount of single name credit default swaps. We entered into these swaps in order to mitigate the credit risk associated with specific securities owned. As of December 31, 2022 and 2021, we held $54.3 million and $41.7 million, respectively, notional amount of foreign currency forwards to mitigate the foreign currency risk associated with specific securities owned. As of December 31, 2022 and 2021, we held $76.9 million and $89.2 million, respectively, notional amount of total return swaps to mitigate the volatility associated with changes in the fair value of the underlying notional assets in our non-qualified defined contribution plan. This derivative is an economic hedge not designated as a hedging instrument, and changes in fair value are reported as a component of other expenses in our income statement. We have an embedded derivative in a modified coinsurance arrangement for which we include in our net investment gains and losses a calculation intended to estimate the value of the option of our reinsurance counterparty to cancel the reinsurance contract with us. However, neither party can unilaterally terminate the reinsurance agreement except in extreme circumstances resulting from regulatory supervision, delinquency proceedings, or other direct regulatory action. Cash settlements or collateral related to this embedded derivative are not required at any time during the reinsurance contract or at termination of the reinsurance contract. There are no credit-related counterparty triggers, and any accumulated embedded derivative gain or loss reduces to zero over time as the reinsured business winds down. Locations and Amounts of Derivative Financial Instruments The following tables summarize the notional amounts and fair values of derivative financial instruments, as reported in our consolidated balance sheets. Derivative assets are included in other long-term investments, while derivative liabilities are included in other liabilities within our consolidated balance sheets. The notional amounts represent the basis upon which our counterparty pay and receive amounts are calculated. December 31, 2022 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Forward Benchmark Interest Rate Locks $ 764.0 $ 1.6 $ 48.4 Foreign Currency Interest Rate Swaps 168.9 17.5 3.1 Total Cash Flow Hedges 932.9 19.1 51.5 Fair Value Hedges Foreign Currency Interest Rate Swaps 557.8 66.0 5.4 Total Designated as Hedging Instruments $ 1,490.7 $ 85.1 $ 56.9 Not Designated as Hedging Instruments Foreign Currency Forwards $ 54.3 $ 4.0 $ 0.1 Foreign Currency Interest Rate Swaps 132.0 — 17.0 Total Return Swaps 76.9 — — Embedded Derivative in Modified Coinsurance Arrangement — — 13.9 Total Not Designated as Hedging Instruments $ 263.2 $ 4.0 $ 31.0 Total Derivatives $ 1,753.9 $ 89.1 $ 87.9 December 31, 2021 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Foreign Currency Interest Rate Swaps $ 181.3 $ 16.2 $ 7.0 Fair Value Hedges Foreign Currency Interest Rate Swaps 498.5 21.9 5.7 Total Designated as Hedging Instruments $ 679.8 $ 38.1 $ 12.7 Not Designated as Hedging Instruments Credit Default Swaps $ 11.6 $ — $ — Foreign Currency Forwards 41.7 — — Foreign Currency Interest Rate Swaps 148.2 1.4 22.3 Total Return Swaps 89.2 — — Embedded Derivative in Modified Coinsurance Arrangement — — 30.1 Total Not Designated as Hedging Instruments $ 290.7 $ 1.4 $ 52.4 Total Derivatives $ 970.5 $ 39.5 $ 65.1 The following tables summarize the location of gains and losses of derivative financial instruments designated as hedging instruments, as reported in our consolidated statements of income. Year Ended December 31, 2022 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 2,122.2 $ (15.7) $ 188.5 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged items 200.0 — 2.9 Derivatives Designated as Hedging Instruments 51.0 — — Foreign Exchange Contracts: Hedged items 12.3 (2.3) — Derivatives Designated as Hedging Instruments (0.8) 1.8 — Forward Benchmark Interest Rate Locks: Hedged items 0.5 — — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged items 11.6 (26.8) — Derivatives Designated as Hedging Instruments 7.3 26.8 — Year Ended December 31, 2021 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 2,213.2 $ 76.7 $ 185.0 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged items 220.4 2.7 29.2 Derivatives Designated as Hedging Instruments 64.6 2.0 5.0 Foreign Exchange Contracts: Hedged items 13.0 (0.1) — Derivatives Designated as Hedging Instruments 1.8 (0.1) — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged items 9.8 (22.3) — Derivatives Designated as Hedging Instruments 4.6 22.3 — Year Ended December 31, 2020 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 2,360.7 $ 1,199.1 $ 188.2 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged items 286.1 397.7 29.2 Derivatives Designated as Hedging Instruments 75.9 32.0 1.7 Foreign Exchange Contracts: Hedged items 12.1 (0.1) — Derivatives Designated as Hedging Instruments 2.5 0.1 — Gain (Loss) on Fair Value Hedging Relationships Interest Rate Swaps: Hedged items — (0.6) 10.1 Derivatives Designated as Hedging Instruments — 0.6 (0.9) Foreign Exchange Contracts: Hedged items 7.1 23.3 — Derivatives Designated as Hedging Instruments 2.8 (23.3) — The following table summarizes the location of gains and losses of derivative financial instruments designated as cash flow hedging instruments, as reported in our consolidated statements of comprehensive income (loss). Year Ended December 31 2022 2021 2020 (in millions of dollars) Gain (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives Forwards $ (49.8) $ (0.6) $ — Foreign Exchange Contracts 7.4 2.2 (5.4) Total $ (42.4) $ 1.6 $ (5.4) The following table summarizes the location of gains and losses on our derivatives not designated as hedging instruments, as reported in our consolidated statements of income. Year Ended December 31 2022 2021 2020 (in millions of dollars) Net Investment Gain (Loss) Credit Default Swaps $ — $ (0.3) $ (0.5) Foreign Exchange Contracts 2.7 3.4 (2.0) Embedded Derivative in Modified Coinsurance Arrangement 16.2 9.7 (17.0) Total $ 18.9 $ 12.8 $ (19.5) Other Expenses (Gain) Loss on Total Return Swaps $ 18.9 $ (8.5) $ —

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Components of our accumulated other comprehensive income (loss), after tax, and related changes are as follows: Net Unrealized Gain (Loss) on Securities Net Gain (Loss) on Hedges Foreign Currency Translation Adjustment Unrecognized Pension and Postretirement Benefit Costs Total (in millions of dollars) Balances at December 31, 2019 $ 615.9 $ 187.8 $ (281.6) $ (484.8) $ 37.3 Other Comprehensive Income (Loss) Before Reclassifications 405.6 (5.7) 20.3 (60.8) 359.4 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 46.2 (84.3) — 15.6 (22.5) Net Other Comprehensive Income (Loss) 451.8 (90.0) 20.3 (45.2) 336.9 Balances at December 31, 2020 1,067.7 97.8 (261.3) (530.0) 374.2 Other Comprehensive Income (Loss) Before Reclassifications (169.9) 14.7 (12.6) 116.3 (51.5) Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 64.4 (50.7) — 17.7 31.4 Net Other Comprehensive Income (Loss) (105.5) (36.0) (12.6) 134.0 (20.1) Balances at December 31, 2021 962.2 61.8 (273.9) (396.0) 354.1 Other Comprehensive Income (Loss) Before Reclassifications (3,009.2) (30.4) (115.2) 49.7 (3,105.1) Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 23.2 (41.0) — 12.2 (5.6) Net Other Comprehensive Income (Loss) (2,986.0) (71.4) (115.2) 61.9 (3,110.7) Balances at December 31, 2022 $ (2,023.8) $ (9.6) $ (389.1) $ (334.1) $ (2,756.6) The net unrealized gain (loss) on securities consists of the following components: December 31 Change for the Year Ended December 31 2022 2021 2020 2019 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities $ (2,984.4) $ 5,949.3 $ 7,597.6 $ 6,364.4 $ (8,933.7) $ (1,648.3) $ 1,233.2 Deferred Acquisition Costs 11.3 (70.4) (85.1) (62.7) 81.7 14.7 (22.4) Reserves for Future Policy and Contract Benefits 566.7 (4,659.5) (6,225.6) (5,803.1) 5,226.2 1,566.1 (422.5) Reinsurance Recoverable (18.1) 132.1 200.2 424.7 (150.2) (68.1) (224.5) Income Tax 400.7 (389.3) (419.4) (307.4) 790.0 30.1 (112.0) Total $ (2,023.8) $ 962.2 $ 1,067.7 $ 615.9 $ (2,986.0) $ (105.5) $ 451.8 Amounts reclassified from accumulated other comprehensive income (loss) were recognized in our consolidated statements of income as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Net Unrealized Loss on Securities Net Investment Gain (Loss) Gain (Loss) on Sales on Securities $ (24.8) $ 60.8 $ 1,279.7 Credit Losses on Fixed Maturity Securities (4.6) (9.3) (53.6) Loss on Benefits and Change in Reserves for Future Benefits — (133.1) (1,284.5) (29.4) (81.6) (58.4) Income Tax Benefit (6.2) (17.2) (12.2) Total $ (23.2) $ (64.4) $ (46.2) Net Gain (Loss) on Hedges Net Investment Income Gain on Interest Rate Swaps and Forwards $ 51.1 $ 60.6 $ 74.1 Gain (Loss) on Foreign Exchange Contracts (1.0) 1.7 2.0 Net Investment Gain (Loss) Gain on Interest Rate Swaps — 2.0 32.0 Gain (Loss) on Foreign Exchange Contracts 1.8 (0.1) 0.1 Interest and Debt Expense Loss on Interest Rate Swaps — — (1.5) 51.9 64.2 106.7 Income Tax Expense 10.9 13.5 22.4 Total $ 41.0 $ 50.7 $ 84.3 Unrecognized Pension and Postretirement Benefit Costs Other Expenses Amortization of Net Actuarial Loss $ (15.7) $ (22.6) $ (19.8) Amortization of Prior Service Credit 0.2 0.2 0.1 Curtailment Gain — — (0.1) (15.5) (22.4) (19.8) Income Tax Benefit (3.3) (4.7) (4.2) Total $ (12.2) $ (17.7) $ (15.6)

Liability for Unpaid Claims and

Liability for Unpaid Claims and Claim Adjustment Expenses	12 Months Ended
	Dec. 31, 2022
Insurance [Abstract]
Liability for Unpaid Claims and Claims Adjustment Expenses Disclosure	Changes in the liability for unpaid claims and claim adjustment expenses are as follows: 2022 2021 2020 (in millions of dollars) Balance at January 1 $ 23,664.7 $ 24,180.2 $ 23,076.7 Less Reinsurance Recoverable 8,697.8 8,378.9 2,246.8 Net Balance at January 1 14,966.9 15,801.3 20,829.9 Incurred Related to Current Year 6,721.3 7,252.6 6,327.8 Prior Years Interest 595.6 683.4 997.8 All Other Incurred (646.0) (719.5) 878.7 Foreign Currency (235.9) (23.4) 65.9 Total Incurred 6,435.0 7,193.1 8,270.2 Paid Related to Current Year (3,062.9) (3,263.4) (2,727.0) Prior Years (3,786.0) (3,774.1) (4,430.3) Total Paid (6,848.9) (7,037.5) (7,157.3) Reserves Ceded Pursuant to Reinsurance Transaction — (990.0) (6,141.5) Net Balance at December 31 14,553.0 14,966.9 15,801.3 Plus Reinsurance Recoverable 8,279.8 8,697.8 8,378.9 Balance at December 31 $ 22,832.8 $ 23,664.7 $ 24,180.2 The majority of the net balances are related to disability claims with long-tail payouts on which interest earned on assets backing liabilities is an integral part of pricing and reserving. Interest accrued on prior year reserves has been calculated on the opening reserve balance less one-half of the year’s claim payments relative to prior years at our average reserve discount rate for the respective periods. "Incurred Related to Prior Years - All Other Incurred" shown in the preceding chart reflects the current year development of the prior year unpaid claims and claim adjustment expenses. For all years presented this line item includes reserve assumption updates as discussed in the following paragraphs. For 2021 and 2020, this amount includes the increase in benefits and change in reserves for future benefits resulting from the realization of previously unrealized investment gains and losses as a result of both phases of the Closed Block individual disability reinsurance transaction. Excluding the reserve assumption updates and impacts from the reinsurance transaction, the variability exhibited year over year is primarily caused by the level of claim resolutions in the period relative to the long-term expectations reflected in the reserves, primarily in our Unum US group long-term disability and Closed Block long-term care product lines. Our claim resolution rate assumption used in determining reserves is our expectation of the resolution rate we will experience over the life of the block of business and will vary from actual experience in any one period, both favorably and unfavorably. Reserve Assumption Updates During 2022, we completed our annual review of policy and claim reserve adequacy, which incorporated our most recent experience and included a review of all material assumptions. Based on our analysis, during 2022, we updated our reserve assumptions to reflect our current estimate of future benefits obligations and determined that our claim reserves in our Unum US group long-term disability product line and our waiver of premium reserves for our Unum US group life product line should be reduced by $121.0 million and $34.0 million, respectively, due primarily to sustained improvement in claim recovery trends since our last assumption update, partially offset by lower social security benefit offsets for our group long-term disability product line. As a result, a reduction of approximately $155.0 million, which can be primarily attributed to prior year incurred claims, impacts the results shown in the preceding chart. We also increased our claim reserves for the reinsured portion of our Closed Block individual disability product line by $193.9 million resulting primarily from updates to mortality assumptions for the advanced age portion of our claimant population. This increase is entirely related to the block that was ceded as a part of the Closed Block individual disability reinsurance transaction with Commonwealth Annuity and Life Insurance Company (Commonwealth). As a result, the increase in the Closed Block individual disability claim reserves had no impact on the net activity shown in the preceding chart. During 2021, we completed our annual review of policy and claim reserve adequacy, which incorporated our most recent experience and included a review of all material assumptions. Based on our analysis, during 2021, we updated our reserve assumptions and determined that our claim reserves should be reduced by $215.0 million in our Unum US group long-term disability product line due primarily to sustained improvement in claim recovery trends since our last assumption update. We also increased our claim reserves for our Closed Block long-term care and individual disability product lines by $2.1 million and $6.4 million, respectively, to reflect our current estimate of future benefit obligations. As a result, a net reduction of approximately $206.5 million, which can be primarily attributed to prior year incurred claims, impacts the results shown in the preceding chart. We also increased policy reserves in our Closed Block group pension product line by $25.1 million as a result of this review which did not affect the results shown in the preceding chart. During 2020, we completed our annual review of policy reserve adequacy, which incorporated our most recent experience and included a review of all material assumptions. Based on our analysis, during 2020, we updated our interest rate and premium rate increase reserve assumptions and determined that our Closed Block long-term care policy and claim reserves should be increased by $151.5 million, of which $7.0 million was related to our liability for unpaid claims and claims adjustment expenses, which can be primarily attributed to prior year incurred claims, thereby impacting the results shown in the preceding chart. We also increased policy reserves in our Closed Block group pension product line by $17.5 million as a result of this review which did not affect the results shown in the preceding chart. Closed Block Individual Disability Reinsurance Transaction In connection with the first phase of the Closed Block individual disability reinsurance transaction that closed in December 2020, we recorded a reinsurance recoverable of $6,141.5 million representing the ceded reserves related to the cohort of policies on claim status as of July 1, 2020 (DLR cohort) and an increase in benefits and change in reserves for future benefits of $1,284.5 million resulting from the realization of previously unrealized investment gains and losses recorded in accumulated other comprehensive income (loss). In connection with the second phase of the Closed Block individual disability transaction that closed in March 2021, we recorded a reinsurance recoverable of $990.0 million representing the ceded reserves related to the cohort of policies on claim status as of January 1, 2021 and an increase in benefits and change in reserves for future benefits of $133.1 million resulting from the realization of previously unrealized investment gains and losses recorded in accumulated other comprehensive income (loss). These impacts are reflected in the chart shown above and the reconciliation shown below. See Note 12 for further discussion regarding the total impacts of the Closed Block individual disability reinsurance transaction. Reconciliation A reconciliation of policy and contract benefits and reserves for future policy and contract benefits as reported in our consolidated balance sheets to the liability for unpaid claims and claim adjustment expenses is as follows: December 31 2022 2021 2020 (in millions of dollars) Policy and Contract Benefits $ 1,839.8 $ 1,907.7 $ 1,855.4 Reserves for Future Policy and Contract Benefits 42,330.2 48,007.5 49,653.0 Total 44,170.0 49,915.2 51,508.4 Less: Life Reserves for Future Policy and Contract Benefits 8,428.5 8,457.1 8,371.7 Accident and Health Active Life Reserves 13,475.4 13,133.9 12,730.9 Adjustment Related to Unrealized Investment Gains (Losses) (566.7) 4,659.5 6,225.6 Liability for Unpaid Claims and Claim Adjustment Expenses $ 22,832.8 $ 23,664.7 $ 24,180.2

Income Tax

Income Tax	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Tax Disclosure	Total income tax expense (benefit) is allocated as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Net Income $ 317.2 $ 238.8 $ 171.0 Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) Change in Net Unrealized Gain (Loss) on Securities Before Adjustment (1,890.8) (346.9) 250.2 Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance 1,100.8 316.8 (138.2) Change in Net Gain (Loss) on Hedges (19.2) (9.8) (23.8) Change in Foreign Currency Translation Adjustment (0.1) 4.2 (4.3) Change in Unrecognized Pension and Postretirement Benefit Costs 18.9 42.1 (34.8) Total $ (473.2) $ 245.2 $ 220.1 A reconciliation of the income tax provision at the U.S. federal statutory rate to the income tax rate as reported in our consolidated statements of income is as follows: Year Ended December 31 2022 2021 2020 Statutory Income Tax 21.0 % 21.0 % 21.0 % Net Operating Loss Carryback — (0.7) (3.8) Tax Exempt Income (1.1) (1.1) (0.8) Tax Credits (0.3) (0.9) (1.3) Policyholder Reserves (1.9) 2.4 0.7 Other Items, Net 1.7 1.8 1.9 Effective Tax 19.4 % 22.5 % 17.7 % Our net deferred tax asset (liability) consists of the following. December 31 2022 2021 (in millions of dollars) Deferred Tax Asset Invested Assets $ 664.9 $ — Reserves — 889.7 Employee Benefits 158.3 176.6 Other 34.4 57.5 Gross Deferred Tax Asset 857.6 1,123.8 Less: Valuation Allowance 10.3 12.7 Net Deferred Tax Asset 847.3 1,111.1 Deferred Tax Liability Deferred Acquisition Costs 113.1 134.9 Fixed Assets 48.9 71.1 Invested Assets — 1,144.9 Reserves 43.2 — Cost of Reinsurance 156.8 171.6 Other 44.7 47.0 Gross Deferred Tax Liability 406.7 1,569.5 Net Deferred Tax Asset (Liability) $ 440.6 $ (458.4) Our consolidated statements of income include amounts subject to both domestic and foreign taxation. The income and related tax expense (benefit) are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Income Before Tax Domestic $ 1,492.8 $ 957.0 $ 924.7 Foreign 138.6 106.0 39.3 Total $ 1,631.4 $ 1,063.0 $ 964.0 Current Tax Expense (Benefit) Federal $ 306.5 $ 180.7 $ (98.4) State and Local 12.7 2.6 1.5 Foreign 154.3 29.5 (19.7) Total 473.5 212.8 (116.6) Deferred Tax Expense (Benefit) Federal 20.9 13.3 250.5 State and Local 1.1 (2.2) 1.0 Foreign (178.3) 14.9 36.1 Total (156.3) 26.0 287.6 Total Tax Expense $ 317.2 $ 238.8 $ 171.0 On June 10, 2021, the Finance Act 2021 was enacted, resulting in a U.K. tax increase from 19 percent to 25 percent, effective April 1, 2023, which resulted in $24.2 million of additional tax expense in operating earnings for the revaluation of our deferred tax assets and liabilities in 2021. On July 22, 2020, the Finance Act 2020 was enacted, resulting in a U.K. tax rate increase from 17 percent to 19 percent, retroactively effective April 1, 2020, which resulted in $9.3 million of additional tax expense for the revaluation of our deferred tax assets and liabilities in 2020. In addition, we recorded a tax benefit of $36.5 million in 2020 for tax losses that were carried back to a tax year in which the U.S. statutory tax rate was 35 percent pursuant to the Coronavirus Aid, Relief, and Economic Security Act (CARES Act). As of December 31, 2022, our plans for future repatriations of cash from our foreign subsidiaries can include no more than the amount of capital above that which is required by U.K. regulatory capital requirements. The remainder of our investment in our foreign subsidiaries is indefinitely reinvested. Our consolidated statements of income include the following changes in unrecognized tax benefits. December 31 2022 2021 2020 (in millions of dollars) Balance at Beginning of Year $ 198.8 $ 219.7 $ 241.0 Decreases for Tax Positions Related to Prior Years (21.0) (20.9) (21.0) Lapse of the Applicable Statute of Limitations (0.4) — (0.3) Balance at End of Year 177.4 198.8 219.7 Less Tax Attributable to Temporary Items Included Above (63.5) (84.7) (105.9) Total Unrecognized Tax Benefits That if Recognized Would Affect the Effective Tax Rate $ 113.9 $ 114.1 $ 113.8 In 2018, we recorded $261.1 million gross unrecognized tax benefits for a policyholder reserves position taken on our 2017 federal tax return, which if recognized, would decrease our tax expense by $112.9 million. The balances of unrecognized tax benefits for which the ultimate deductibility is highly certain but for which there is uncertainty about the timing of such deductibility are $63.5 million at December 31, 2022, $84.7 million at December 31, 2021, and $105.9 million at December 31, 2020. It is reasonably possible that this item could reverse in the next 12 months following review by the IRS. We recognize interest expense and penalties, if applicable, related to unrecognized tax benefits in tax expense. We recognized $7.8 million, $5.5 million, and $7.8 million of interest expense related to unrecognized tax benefits during 2022, 2021, and 2020, respectively. The liability for net interest expense on uncertain tax positions was approximately $34.0 million, $26.2 million, and $20.6 million as of December 31, 2022, 2021, and 2020, respectively. We file federal and state income tax returns in the United States and in foreign jurisdictions. Tax year 2017 and tax years subsequent to 2018 remain subject to examination by the IRS. All major foreign jurisdictions remain subject to examination for tax years subsequent to 2020 with the exception of Poland for which tax years subsequent to 2016 remain subject to examination. We believe sufficient provision has been made for all potential adjustments for years that are not closed by the statute of limitations in all major tax jurisdictions and that any such adjustments would not have a material adverse effect on our financial position, liquidity, or results of operations. We file state income tax returns in nearly every state in the United States. Tax years subsequent to 2016 remain subject to examination depending on the statute of limitation established by the various states, which is generally three to four years. As of December 31, 2022, we have no federal net operating loss or capital loss carryforwards. We have net operating loss carryforwards for state and local income tax of approximately $187.6 million, most of which is expected to expire unused between 2023 and 2042. We record valuation allowances to reduce deferred tax assets to the amount that is more likely than not to be realized. Our valuation allowance was $10.3 million and $12.7 million at December 31, 2022 and 2021, respectively, the majority of which related to our cumulative deferred state income tax benefits. The de minimis remaining amount of our valuation allowance relates to unrealized tax losses on buildings which we own and occupy in the U.K. We recorded a decrease in our valuation allowance of $2.4 million during 2022 and a decrease of $1.8 million in 2021, primarily in other comprehensive income. Total income taxes paid during 2022 were $375 million. Total income taxes refunded during 2021 were $51 million. Total income taxes paid during 2020 were $200 million.

Debt

Debt	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Debt	Debt consists of the following: December 31 2022 2021 Interest Rates Maturities (in millions of dollars) Outstanding Principal Senior Notes issued 1998 6.750 - 7.250% 2028 $ 335.8 $ 335.8 Senior Notes issued 2002 7.375% 2032 39.5 39.5 Senior Notes issued 2012 and 2016 5.750% 2042 500.0 500.0 Senior Notes issued 2014 4.000% 2024 — 350.0 Senior Notes issued 2015 3.875% 2025 275.0 275.0 Senior Notes issued 2019 4.000% 2029 400.0 400.0 Senior Notes issued 2019 4.500% 2049 450.0 450.0 Senior Notes issued 2021 4.125% 2051 600.0 600.0 Medium-term Notes issued 1990 - 1996 7.000 - 7.190% 2023 - 2028 18.5 20.5 Junior Subordinated Debt Securities issued 1998 7.405% 2038 189.7 203.7 Junior Subordinated Debt Securities issued 2018 6.250% 2058 300.0 300.0 Term Loan issued 2022 Variable 2027 350.0 — Less: Unamortized Net Premium 2.5 2.3 Unamortized Debt Issuance Costs (33.2) (34.6) Total Long-term Debt $ 3,427.8 $ 3,442.2 Short-term Debt Medium-term Notes Issued 1990 7.000% 2023 2.0 — Total Debt $ 3,429.8 $ 3,442.2 Long-term debt is comprised of our unsecured notes, which consist of our senior notes, medium-term notes, and term loan facility, and rank highest in priority, followed by our junior subordinated debt securities. The senior notes are callable and may be redeemed, in whole or in part, at any time. The term loan facility is callable and may be redeemed at par at any time. The medium-term notes are non-callable and the junior subordinated debt securities are callable under limited, specified circumstances. The aggregate contractual principal maturities are $2.0 million in 2023, $275.0 million in 2025, $350.0 million in 2027 and $2,833.5 million thereafter. Unsecured Notes In August 2022, we redeemed $350.0 million aggregate principal amount of our 4.000% senior notes due 2024, for which we incurred costs of $3.0 million and has been recorded within cost related to the early retirement of debt in the consolidated statements of income and is included within our Corporate segment. In June 2021, we issued $600.0 million of 4.125% senior notes due 2051. The notes are callable at or above par and rank equally in the right of payment with all of our other unsecured and unsubordinated debt. In September 2020, our $400.0 million 5.625% senior unsecured notes matured. In May 2020, we issued $500.0 million of 4.500% senior notes due 2025. In June 2021, we purchased and retired these senior notes, for which we incurred costs of $67.3 million and has been recorded within cost related to the early retirement of debt in the consolidated statements of income and is included within our Corporate segment. Term Loan Facility In August 2022, we entered into a five-year $350.0 million senior unsecured delayed draw term loan facility with a syndicate of lenders. Also in August 2022 , we drew the entire amount of the term loan facility, which is scheduled to mature in August 2027. Amounts due under the term loan facility incur interest based on the prime rate, the federal funds rate, or the Secured Overnight Financing Rate (SOFR). The proceeds from the term loan facility were used to redeem $350.0 million aggregate principal amount of our 4.000% senior notes due 2024. Borrowings under the term loan facility are subject to financial covenants, negative covenants, and events of default that are customary. The term loan facility includes financial covenants based on our leverage ratio and consolidated net worth. Senior Secured Notes In 2007, Northwind Holdings, LLC (Northwind Holdings), a wholly-owned subsidiary of Unum Group, issued $800.0 million of insured, senior secured notes, bearing interest at a floating rate equal to the three month LIBOR plus 0.78% (the Northwind notes) in a private offering. Northwind Holdings made periodic principal payments on the Northwind notes of $45.0 million in 2020. In December 2020, Northwind Holdings redeemed the remaining $35.0 million of principal on the Northwind notes, and was released of any contractual collateral requirements. Fair Value Hedges As of December 31, 2019, we had $250.0 million notional amount of an interest rate swap which effectively converted certain of our unsecured senior notes into floating rate debt. Under this agreement, we received a fixed rate of interest and paid a variable rate of interest, based off of three-month LIBOR. During 2020, the $250.0 million notional amount of the interest rate swap matured in conjunction with the maturity of the hedged debt. See Note 4 for further information on the interest rate swap. Junior Subordinated Debt Securities In 1998, Provident Financing Trust I (the Trust), a 100 percent-owned finance subsidiary of Unum Group, issued $300.0 million of 7.405% capital securities due 2038 in a public offering. These capital securities are fully and unconditionally guaranteed by Unum Group, have a liquidation value of $1,000 per capital security, and have a mandatory redemption feature under certain circumstances. In connection with the capital securities offering, Unum Group issued to the Trust 7.405% junior subordinated deferrable interest debentures due 2038. The Trust is a variable interest entity of which Unum Group is not the primary beneficiary. Accordingly, the capital securities issued by the Trust are not included in our consolidated financial statements and our liability represents the junior subordinated debt securities owed to the trust which is recorded in long-term debt. The sole assets of the Trust are the junior subordinated debt securities. The retirement of any liquidation amount regarding the capital securities by the Trust results in a corresponding retirement of principal amount of the junior subordinated debt securities. In September 2022, pursuant to privately negotiated transactions, we purchased, and the Trust retired, $14.0 million aggregate liquidation amount of the Trust's 7.405% capital securities due 2038, which resulted in the reduction of a corresponding principal amount of our 7.405% junior subordinated debt securities due 2038 then held by the Trust. We incurred costs of $1.2 million related to the early retirement of the junior subordinated debt securities. Interest Paid Interest paid on long-term and short-term debt and related securities during 2022, 2021, and 2020 was $172.9 million, $181.6 million, and $178.1 million, respectively. Credit Facilities In April 2022, we amended and restated our existing credit agreement providing for a five-year $500.0 million senior unsecured revolving credit facility with a syndicate of lenders. The credit facility, which was previously set to expire in April 2024, was extended through April 2027. We may request that the lenders’ aggregate commitments of $500.0 million under the facility be increased by up to an additional $200.0 million. Certain of our traditional U.S. life insurance subsidiaries, Unum Life Insurance Company of America (Unum America), Provident Life and Accident Insurance Company (Provident), and Colonial Life & Accident Insurance Company, joined the agreement and may borrow under the credit facility, and we can elect to add additional insurance subsidiaries to the facility at any later date. Any obligation of a subsidiary under the credit facility is several only and not joint and is subject to an unconditional guarantee by Unum Group. We may also request, on up to two occasions, that the lenders' commitment termination dates be extended by one year. The credit facility also provides for the issuance of letters of credit subject to certain terms and limitations. The credit facility provides for borrowings at an interest rate based on the prime rate, the federal funds rate or the SOFR. At December 31, 2022, there were no borrowed amounts outstanding under the credit facility and letters of credit totaling $0.4 million had been issued. In the third quarter of 2021, we terminated our three-year, $100.0 million unsecured revolving credit facility, which was originally set to expire in April 2022. There were no letters of credit issued from the credit facility and there were no borrowed amounts outstanding at the time of termination. Also in the third quarter of 2021, we entered into a new five-year, £75 million unsecured standby letter of credit facility with the same syndicate of lenders, pursuant to which a syndicated letter of credit was issued in favor of Unum Limited (as beneficiary), our U.K. insurance subsidiary, and is available for drawings up to £75 million until its scheduled expiration in July 2026. The credit facility provides for borrowings at an interest rate based either on the prime rate or federal funds rate. No amounts have been drawn on the letter of credit. If drawings are made in the future, we may elect to borrow such amounts from the lenders pursuant to term loans made under the credit facility. Borrowings under the credit facilities are subject to financial covenants, negative covenants, and events of default that are customary. The two primary financial covenants include limitations based on our leverage ratio and consolidated net worth. We are also subject to covenants that limit subsidiary indebtedness. Facility Agreement for Contingent Issuance of Senior Notes During November 2021, we entered into a 20-year facility agreement with a Delaware trust in connection with the sale by the trust of $400.0 million of pre-capitalized trust securities in a Rule 144A private placement. The trust invested the proceeds from the sale of the trust securities in a portfolio of principal and interest strips of U.S. Treasury securities. The facility agreement provides us the right to issue and sell to the trust, on one or more occasions, up to an aggregate principal amount outstanding at any one time of $400.0 million of our 4.046% senior notes which would be due August 15, 2041 in exchange for U.S. Treasury securities held by the trust. These senior notes will not be issued unless and until the issuance right is exercised. In return, we will pay a semi-annual facility fee to the trust at a rate of 2.225% per year on the unexercised portion of the maximum amount of senior notes that we could issue and sell to the trust and we will reimburse the trust for its expenses. We may also direct the trust to grant the right to exercise the issuance right with respect to all or a designated amount of the senior notes to one or more assignees (who are our consolidated subsidiaries or persons to whom we have an obligation). The issuance right will be exercised automatically in full upon our failure to make certain payments to the trust, such as paying the facility fee or reimbursing the trust for its expenses, if the failure to pay is not cured within 30 days, or upon certain bankruptcy events involving the company. We are also required to exercise the issuance right in full if our consolidated stockholders’ equity, excluding accumulated other comprehensive income, falls below $2.0 billion, subject to adjustment from time to time in certain cases, and upon certain other events described in the facility agreement. Prior to any involuntary exercise of the issuance right, we have the right to repurchase any or all of the 4.046% senior notes then held by the trust in exchange for U.S. Treasury securities. We may redeem any outstanding 4.046% senior notes, in whole or in part, prior to their maturity. Prior to February 15, 2041, the redemption price will equal the greater of par or a make-whole redemption price. On or after February 15, 2041, any outstanding 4.046% senior notes may be redeemed at par.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits Disclosure	Defined Benefit Pension and Other Postretirement Benefit (OPEB) Plans We sponsor several defined benefit pension and OPEB plans for our employees, including non-qualified pension plans. The U.S. qualified and non-qualified defined benefit pension plans comprise the majority of our total benefit obligation and benefit cost. We maintain a separate defined benefit plan for eligible employees in our U.K. operation. The U.S. defined benefit pension plans were closed to new entrants on December 31, 2013, the OPEB plan was closed to new entrants on December 31, 2012, and the U.K. plan was closed to new entrants on December 31, 2002. Amortization Period of Actuarial Gain or Loss and Prior Service Cost or Credit Because all participants in the U.S. and U.K. pension plans are considered inactive, we amortize the net actuarial gain or loss and prior service credit or cost for these plans over the average remaining life expectancy of the plans. As of December 31, 2022, the estimate of the average remaining life expectancy of the plans was approximately 24 years for the U.S. plan and 28 years for the U.K. plan. For the OPEB plan, we amortize the net actuarial gain or loss and prior service credit or cost for this plan over the average remaining future working lifetime for active participants in the plan. As of December 31, 2022, the estimate of the average remaining future working lifetime was approximately 2 years for the OPEB plan. The following table provides the changes in the benefit obligation and fair value of plan assets and the funded status of the plans. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 (in millions of dollars) Change in Benefit Obligation Benefit Obligation at Beginning of Year $ 2,207.5 $ 2,277.2 $ 278.3 $ 300.0 $ 110.3 $ 120.5 Service Cost 7.7 9.6 — — — — Interest Cost 67.2 65.0 5.0 4.2 3.0 3.0 Plan Participant Contributions — — — — 0.1 0.1 Actuarial Gain (1) (604.1) (57.9) (92.4) (18.0) (19.4) (3.0) Benefits and Expenses Paid (92.8) (86.4) (5.4) (5.2) (10.1) (10.3) Change in Foreign Exchange Rates — — (27.6) (2.7) — — Benefit Obligation at End of Year $ 1,585.5 $ 2,207.5 $ 157.9 $ 278.3 $ 83.9 $ 110.3 Accumulated Benefit Obligation at December 31 $ 1,585.5 $ 2,207.5 $ 158.0 $ 276.5 N/A N/A Change in Fair Value of Plan Assets Fair Value of Plan Assets at Beginning of Year $ 1,801.7 $ 1,710.9 $ 303.7 $ 294.1 $ 9.0 $ 9.3 Actual Return on Plan Assets (410.6) 167.6 (128.4) 18.0 0.1 0.1 Employer Contributions 10.0 9.6 — — 9.4 9.8 Plan Participant Contributions — — — — 0.1 0.1 Benefits and Expenses Paid (92.8) (86.4) (5.4) (5.2) (10.1) (10.3) Change in Foreign Exchange Rates — — (29.4) (3.2) — — Fair Value of Plan Assets at End of Year $ 1,308.3 $ 1,801.7 $ 140.5 $ 303.7 $ 8.5 $ 9.0 Underfunded (Overfunded) Status $ 277.2 $ 405.8 $ 17.4 $ (25.4) $ 75.4 $ 101.3 (1) The actuarial gains recognized in 2022 and 2021 for the U.S., OPEB, and U.K. plans were primarily driven by increases in the discount rate assumption. The amounts recognized in our consolidated balance sheets for our pension and OPEB plans at December 31, 2022 and 2021 are as follows. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 (in millions of dollars) Current Liability $ 8.8 $ 8.4 $ — $ — $ 1.1 $ 1.4 Noncurrent Liability 268.4 397.4 17.4 — 74.3 99.9 Noncurrent Asset — — — (25.4) — — Underfunded (Overfunded) Status $ 277.2 $ 405.8 $ 17.4 $ (25.4) $ 75.4 $ 101.3 Unrecognized Pension and Postretirement Benefit Costs Net Actuarial Gain (Loss) $ (517.8) $ (621.8) $ (83.7) $ (42.9) $ 31.6 $ 13.6 Prior Service Credit (Cost) (0.6) (0.6) (0.2) (0.2) 2.5 2.7 (518.4) (622.4) (83.9) (43.1) 34.1 16.3 Income Tax 213.5 239.2 19.5 9.1 1.1 4.9 Total Included in Accumulated Other Comprehensive Income (Loss) $ (304.9) $ (383.2) $ (64.4) $ (34.0) $ 35.2 $ 21.2 The following table provides the changes recognized in other comprehensive income for the years ended December 31, 2022 and 2021. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 (in millions of dollars) Accumulated Other Comprehensive Income (Loss) at Beginning of Year $ (383.2) $ (494.6) $ (34.0) $ (54.7) $ 21.2 $ 19.3 Net Actuarial Gain (Loss) Amortization 16.3 21.3 0.4 1.3 (1.0) — All Other Changes 87.7 124.8 (41.2) 26.3 19.0 2.6 Prior Service Credit (Cost) Amortization — — — — (0.2) (0.2) Change in Income Tax (25.7) (34.7) 10.4 (6.9) (3.8) (0.5) Accumulated Other Comprehensive Income (Loss) at End of Year $ (304.9) $ (383.2) $ (64.4) $ (34.0) $ 35.2 $ 21.2 Plan Assets The objective of our U.S. pension and OPEB plans is to maximize long-term return, within acceptable risk levels, in a manner that is consistent with the fiduciary standards of the Employee Retirement Income Security Act (ERISA), while maintaining sufficient liquidity to pay current benefits and expenses. Our U.S. qualified defined benefit pension plan assets include a diversified blend of domestic, international, global, and emerging market equity securities, fixed income securities, opportunistic credit securities, real estate investments, alternative investments, and cash equivalents. Equity securities are comprised of funds and individual securities that are benchmarked against the respective indices specified below. International and global equity funds may allocate a certain percentage of assets to forward currency contracts. Fixed income securities include funds and U.S. government and agency asset-backed securities, treasury futures contracts, corporate investment-grade bonds, private placement securities, and bonds issued by states or other municipalities. Opportunistic credits consist of investments in funds that hold varied fixed income investments purchased at depressed values with the intention to later sell those investments for a gain. Real estate investments consist primarily of funds that hold commercial real estate investments. Alternative investments, which include private equity direct investments and private equity funds of funds, utilize proprietary strategies that are intended to have a low correlation to the U.S. stock market. Prohibited investments include, but are not limited to, unlisted securities, options, short sales, and investments in securities issued by Unum Group or its affiliates. The invested asset classes, asset types, and benchmark indices for our U.S. qualified defined benefit pension plan is as follows. We target approximately 38 percent to equity securities, 30 percent to fixed income securities, and 32 percent to opportunistic credits, alternative, and real estate investments. Asset Class Asset Type Benchmark Indices Equity Securities Collective funds; Individual holdings Morgan Stanley Capital International (MSCI) World Index Fixed Income Collective funds; Individual holdings Bloomberg Barclays Long Corporate Index; Custom Index Opportunistic Credits Collective fund Custom Index Real Estate Collective fund Custom Index Alternative Investments (Private Equity) Fund of funds; Direct investments Custom Index The investment strategy for our U.K. pension includes increasing the funded ratio in a risk-controlled manner where the risk taken in the investment strategy reduces as the funded status of the plan increases. Assets for our U.K. pension plan are invested in a portfolio of diversified growth assets as well as a portfolio of fixed income and index-linked securities. The portfolio of growth assets consists of funds invested primarily in global equity securities, investment-grade and below-investment-grade fixed interest securities, including emerging market securities as well as diversified alternatives. The portfolio of fixed interest and index-linked securities are invested primarily in leveraged interest rate and inflation-linked gilt funds of varying durations designed to broadly match the interest rate and inflation sensitivities of the plan's liabilities. At December 31, 2022, our target allocation was approximately 50 percent to growth assets and 50 percent to fixed interest and index-linked securities. When the funded status of the plan increases, we utilize a de-risking framework whereby the allocation to fixed interest and index-linked securities increases and the allocation to growth assets is lowered. Simultaneously, the hedge ratio of interest rate and inflation risk will increase with the intention of reducing funding level volatility. There are no categories of investments that are specifically prohibited by the U.K. plan, but there are general guidelines that ensure prudent investment action is taken. Such guidelines include the prevention of the plan from using derivatives for speculative purposes and limiting the concentration of risk in any one type of investment. Assets for the OPEB plan are invested in life insurance contracts issued by one of our insurance subsidiaries. The assets support life insurance benefits payable to certain former retirees covered under the OPEB plan. The terms of these contracts are consistent in all material respects with those the subsidiary offers to unaffiliated parties that are similarly situated. There are no categories of investments specifically prohibited by the OPEB plan. We believe our investment portfolios are well diversified by asset class and sector, with no undue risk concentrations in any one category. The categorization of fair value measurements by input level for the invested assets in our U.S. pension plans is shown below. The carrying values of investment-related receivables and payables approximate fair value due to the short-term nature of the securities and are not included in the following chart. Investments valued using net asset value (NAV) as a practical expedient are not required to be categorized by input level, but these investments are included as follows to reconcile to total invested assets. Certain prior year amounts were reclassified to conform to current year presentation. December 31, 2022 Quoted Prices Significant Other Significant NAV as a Practical Total (in millions of dollars) Invested Assets Equity Securities: Global $ 57.4 $ — $ — $ 405.7 $ 463.1 Fixed Income Securities: U.S. Government and Agencies 1 194.0 21.7 — — 215.7 Corporate — — — 129.6 129.6 Non-U.S. Emerging Markets — — — 54.0 54.0 Opportunistic Credits — — — 132.3 132.3 Real Estate — — — 164.2 164.2 Alternative Investments: Private Equity Direct Investments — — — 74.5 74.5 Private Equity Funds of Funds — — — 47.6 47.6 Cash Equivalents 20.5 — — — 20.5 Total Invested Assets $ 271.9 $ 21.7 $ — $ 1,007.9 $ 1,301.5 1 U.S. Government and Agencies Fixed Income Securities includes derivative assets. December 31, 2021 Quoted Prices Significant Significant NAV as a Practical Total (in millions of dollars) Invested Assets Equity Securities: U.S. Large Cap $ — $ — $ — $ 144.9 $ 144.9 U.S. Small Cap 32.8 — — 30.5 63.3 Global — — — 388.7 388.7 Emerging Markets — — — 59.8 59.8 Fixed Income Securities: U.S. Government and Agencies 1 419.3 — — — 419.3 Corporate — — — 103.3 103.3 Opportunistic Credits — — — 212.5 212.5 Real Estate — — — 247.1 247.1 Alternative Investments: Private Equity Direct Investments — — — 80.4 80.4 Private Equity Funds of Funds — — — 50.5 50.5 Cash Equivalents 31.9 — — — 31.9 Total Invested Assets $ 484.0 $ — $ — $ 1,317.7 $ 1,801.7 1 U.S. Government and Agencies Fixed Income Securities includes derivative assets. Level 1 investments consist of individual holdings that are valued based on unadjusted quoted prices from active markets for identical securities. Level 2 investments consist of individual holdings that are valued using either directly or indirectly observable inputs other than quoted prices from active markets. Certain equity, opportunistic credit, fixed-income securities, and real estate investments are valued based on the NAV of the underlying holdings as of the reporting date. We made no adjustments to the NAV for 2022 or 2021. These investments have no unfunded commitments and no specific redemption restrictions. Alternative investments are valued based on NAV in a period ranging from one month to one quarter in arrears. We evaluate the need for adjustments to the NAV based on market conditions and discussions with fund managers in the period subsequent to the valuation date and prior to issuance of the financial statements. We made no adjustments to the NAV for 2022 or 2021. The private equity direct investments and private equity funds of funds generally cannot be redeemed by investors. Distributions of capital from the sale of underlying fund assets may occur at any time, but are generally concentrated between five The categorization of fair value measurements by input level for the invested assets in our U.K. pension plan is shown below. Investments valued using NAV as a practical expedient are not required to be categorized by input level, but these investments are included as follows to reconcile to total invested assets. December 31, 2022 Quoted Prices Significant Significant NAV as a Practical Total (in millions of dollars) Invested Assets Diversified Growth Assets $ 32.3 $ — $ — $ 8.3 $ 40.6 Fixed Income and Index-linked Securities 70.6 — — — 70.6 Alternative Investments — — — 28.1 28.1 Cash Equivalents 1.9 — — — 1.9 Total Invested Assets $ 104.8 $ — $ — $ 36.4 $ 141.2 December 31, 2021 Quoted Prices Significant Significant NAV as a Practical Total (in millions of dollars) Invested Assets Diversified Growth Assets $ 113.1 $ — $ — $ 44.2 $ 157.3 Fixed Income and Index-linked Securities 124.1 — — — 124.1 Alternative Investments — — — 18.2 18.2 Cash Equivalents 4.1 — — — 4.1 Total Invested Assets $ 241.3 $ — $ — $ 62.4 $ 303.7 The level 1 diversified growth assets and fixed interest and index-linked securities consist of individual funds that are valued based on unadjusted quoted prices from active markets for identical securities. Certain diversified growth assets were valued based on the NAV of the underlying holdings as of the reporting date. Alternative investments are valued based on NAV one quarter in arrears. We evaluate the need for adjustments to the NAV of the alternative investments based on an evaluation of cash flows in the period subsequent to the valuation date and prior to issuance of the financial statements. We made no adjustments to the NAV for 2022 or 2021. These investments generally cannot be redeemed by investors. These investments had unfunded commitments at December 31, 2022 and 2021 of $17.3 million and $28.1 million, respectively. The categorization of fair value measurements by input level for the assets in our OPEB plan is as follows: December 31, 2022 Quoted Prices Significant Other Significant Total (in millions of dollars) Assets Life Insurance Contracts $ — $ — $ 8.5 $ 8.5 December 31, 2021 Quoted Prices Significant Other Significant Total (in millions of dollars) Assets Life Insurance Contracts $ — $ — $ 9.0 $ 9.0 The fair value is represented by the actuarial present value of future cash flows of the contracts. Changes in our OPEB plan assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended December 31, 2022 and 2021 are as follows: Year Ended December 31, 2022 Beginning Actual Return on Plan Assets Contributions Net Benefits and Expenses Paid End of Year (in millions of dollars) Life Insurance Contracts $ 9.0 $ 0.1 $ 9.5 $ (10.1) $ 8.5 Year Ended December 31, 2021 Beginning Actual Return on Plan Assets Contributions Net Benefits and Expenses Paid End of Year (in millions of dollars) Life Insurance Contracts $ 9.3 $ 0.1 $ 9.9 $ (10.3) $ 9.0 For the years ended December 31, 2022 and 2021, the actual return on plan assets relates solely to investments still held at the reporting date. There were no transfers into or out of Level 3 during 2022 or 2021. Measurement Assumptions We use a December 31 measurement date for each of our plans. The weighted average assumptions used in the measurement of our benefit obligations as of December 31 and our net periodic benefit costs for the years ended December 31 are as follows: Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 Benefit Obligations Discount Rate 5.70 % 3.10 % 4.80 % 2.00 % 5.70 % 2.90 % Rate of Compensation Increase N/A N/A 2.50 % 2.90 % N/A N/A Net Periodic Benefit Cost Discount Rate 3.10 % 2.90 % 2.00 % 1.40 % 2.90 % 2.60 % Expected Return on Plan Assets 6.00 % 6.00 % 4.20 % 3.50 % 5.75 % 5.75 % Rate of Compensation Increase N/A N/A 2.90 % 2.80 % N/A N/A We set the discount rate assumption annually for each of our retirement-related benefit plans at the measurement date to reflect the yield on a portfolio of high quality fixed income corporate debt instruments matched against projected cash flows for future benefits. Our long-term rate of return on plan assets assumption is selected from a range of probable return outcomes from an analysis of the asset portfolio. Our expectations for the future investment returns of the asset categories are based on a combination of historical market performance, evaluations of investment forecasts obtained from external consultants and economists, and current market yields. The methodology underlying the return assumption includes the various elements of the expected return for each asset class such as long-term rates of return, volatility of returns, and the correlation of returns between various asset classes. The expected return for the total portfolio is calculated based on the plan's strategic asset allocation. Investment risk is measured and monitored on an ongoing basis through annual liability measurements, periodic asset/liability studies, and quarterly investment portfolio reviews. Risk tolerance is established through consideration of plan liabilities, plan funded status, and corporate financial condition. Our mortality rate assumption reflects our best estimate, as of the measurement date, of the life expectancies of plan participants in order to determine the expected length of time for benefit payments. We derive our assumptions from industry mortality tables. The expected return assumption for the life insurance reserve for our OPEB plan is based on full investment in fixed income securities with an average book yield of 4.31 percent and 4.59 percent in 2022 and 2021, respectively. The rate of compensation increase assumption for our U.K. pension plan is generally based on periodic studies of compensation trends. At December 31, 2022 and 2021, the annual rates of increase in the per capita cost of covered postretirement health care benefits assumed for the next calendar year are 7.00 percent and 6.25 percent, respectively, for benefits payable to both retirees prior to Medicare eligibility as well as Medicare eligible retirees. The rates are assumed to change gradually to 5.00 percent by 2031 for measurement at December 31, 2022 and remain at that level thereafter. The annual rates of increase in the per capita cost of covered postretirement health benefits do not apply to retirees whose postretirement health care benefits are provided through an exchange. Net Periodic Benefit Cost The following table provides the components of the net periodic benefit cost (credit) for the years ended December 31. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2020 2022 2021 2020 2022 2021 2020 (in millions of dollars) Service Cost $ 7.7 $ 9.6 $ 11.0 $ — $ — $ — $ — $ — $ — Interest Cost 67.2 65.0 73.0 5.0 4.2 4.9 3.0 3.0 4.1 Expected Return on Plan Assets (105.9) (100.6) (106.7) (10.9) (9.8) (9.5) (0.5) (0.5) (0.5) Amortization of: Net Actuarial Loss (Gain) 16.3 21.3 18.7 0.4 1.3 1.1 (1.0) — — Prior Service Cost (Credit) — — 0.1 — — — (0.2) (0.2) (0.2) Curtailment Gain — — — — — 0.1 — — — Total Net Periodic Benefit Cost (Credit) $ (14.7) $ (4.7) $ (3.9) $ (5.5) $ (4.3) $ (3.4) $ 1.3 $ 2.3 $ 3.4 The service cost component of net periodic pension and postretirement benefit cost (credit) is included as a component of compensation expense in our consolidated statements of income. All other components of net periodic pension and postretirement benefit cost (credit) are included in other expenses. Benefit Payments The following table provides expected benefit payments, which reflect expected future service, as appropriate. Pension Benefits U.S. Plans U.K. Plan OPEB (in millions of dollars) Year Gross Subsidy Payments Net 2023 $ 84.9 $ 5.4 $ 10.0 $ 0.1 $ 9.9 2024 88.2 5.5 9.4 0.1 9.3 2025 92.1 5.7 9.0 0.1 8.9 2026 96.5 5.8 8.5 — 8.5 2027 100.6 6.0 8.1 — 8.1 2028-2032 550.6 32.4 34.0 0.1 33.9 Funding Policy The funding policy for our U.S. qualified defined benefit pension plan is to contribute an amount at least equal to the minimum contributions required under ERISA and other applicable laws, but generally not greater than the maximum amount that can be deducted for federal income tax purposes. We had no regulatory contribution requirements for our U.S. qualified defined benefit pension plan in 2022 and made no amount of voluntary contributions during 2022. We do not expect to have regulatory contribution requirements for our U.S. qualified defined benefit pension plan in 2023, but we reserve the right to make voluntarily contributions during 2023. The funding policy for our U.S. non-qualified defined benefit pension plan, which is not subject to ERISA, is to contribute the amount necessary to satisfy the liabilities of the plan as they come due to participants. We expect to make contributions to the U.S. non-qualified defined benefit pension plan of approximately $9 million to fund the benefit payments in 2023. We had no regulatory contribution requirements for our U.K. defined benefit pension plan in 2022 and made no amount of voluntary contributions during 2022. We do not expect to have regulatory contribution requirements for our U.K. defined benefit pension plan in 2023, but we reserve the right to make voluntarily contributions during 2023. Our OPEB plan represents a non-vested, non-guaranteed obligation, and current regulations do not require specific funding levels for these benefits, which are comprised of retiree life, medical, and dental benefits. It is our practice to use general assets to pay medical and dental claims as they come due in lieu of utilizing plan assets for the medical and dental benefit portions of our OPEB plan. Defined Contribution Plans We offer a 401(k) plan to all eligible U.S. employees under which a portion of employee contributions is matched. We match dollar-for-dollar up to 5.0 percent of base salary and any recognized sales and performance-based incentive compensation for employee contributions into the plan. We also make an additional non-elective contribution of 4.5 percent of earnings for all eligible employees and made a separate transition contribution for eligible employees who met certain age and years of service criteria as of December 31, 2013. The separate transition contributions continued through December 31, 2020, at which point they ended. The 401(k) plan remains in compliance with ERISA guidelines and continues to qualify for a “safe harbor” from most annual discrimination testing. We also offer a defined contribution plan to all eligible U.K. employees and offer related employer contributions. If an employee elects to make a minimum contribution of at least 1.0 percent of their base salary, we match with a contribution of 8.0 percent. We increase our contribution to a maximum of 12.0 percent as the employee increases their contribution from 1.0 percent to 5.0 percent. We do not increase our contribution percentage on employee contributions in excess of 5.0 percent. During the years ended December 31, 2022, 2021, and 2020, we recognized costs of $70.9 million, $71.0 million, and $83.4 million, respectively, for our U.S. defined contribution plan. We recognized costs of $4.9 million, $4.9 million, and $5.0 million in 2022, 2021, and 2020, respectively, for our U.K. defined contribution plan.

Stockholders' Equity and Earnin

Stockholders' Equity and Earnings Per Common Share	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity and Earnings Per Common Share [Abstract]
Earnings Per Share Disclosure	Earnings Per Common Share Net income per common share is determined as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars, except share data) Numerator Net Income $ 1,314.2 $ 824.2 $ 793.0 Denominator (000s) Weighted Average Common Shares - Basic 200,647.2 204,232.9 203,642.0 Dilution for Assumed Exercises of Stock Options and Nonvested Stock Awards 1,462.2 615.0 113.3 Weighted Average Common Shares - Assuming Dilution 202,109.4 204,847.9 203,755.3 Net Income Per Common Share Basic $ 6.55 $ 4.04 $ 3.89 Assuming Dilution $ 6.50 $ 4.02 $ 3.89 We compute basic earnings per share by dividing net income by the weighted average number of common shares outstanding for the period. In computing earnings per share assuming dilution, we include potential common shares that are dilutive (those that
Stockholders' Equity Disclosure	Common Stock As part of our capital deployment strategy, we may repurchase shares of Unum Group's common stock, as authorized by our board of directors. The timing and amount of repurchase activity is based on market conditions and other considerations, including the level of available cash, alternative uses for cash, and our stock price. In October 2021, our board of directors authorized the repurchase of up to $250.0 million of Unum Group's outstanding common stock. The October 2021 share repurchase program expired on December 31, 2022, at which point there was no remaining repurchase amount under the program. During 2020 and the first nine months of 2021, there was no authorized share repurchase program. In December 2022, our board of directors authorized the repurchase of up to $200.0 million of Unum Group's outstanding common stock beginning on January 1, 2023. In February 2023, our board of directors authorized an increase to the share repurchase program such that we are now authorized to repurchase up to $250.0 million of Unum Group's outstanding common stock. This share repurchase program has an expiration date of December 31, 2023. Common stock repurchases, which are accounted for using the cost method and classified as treasury stock until otherwise retired, were as follows: Year Ended December 31 2022 2021 2020 (in millions) Shares Repurchased 5.7 1.9 — Cost of Shares Repurchased 1 $ 200.1 $ 50.0 $ — 1 Includes commissions of $0.1 million for the year ended December 31, 2022. In February 2022, we entered into an accelerated share repurchase agreement with a financial counterparty to repurchase $50.0 million of Unum Group's common stock in aggregate. As part of this transaction, we paid $50.0 million to the financial counterparty and received an initial delivery of 1.3 million shares of our common stock, which represented approximately 75 percent of the total delivery under the agreement. We simultaneously entered into a forward contract indexed to the price of Unum Group common stock, which subjected the transaction to a future price adjustment. Under the terms of the share repurchase agreement, we were to receive, or be required to pay, a price adjustment based on the volume weighted average price of Unum Group common stock during the term of the agreement, less a discount. Any price adjustment payable to us was to be settled in shares of Unum Group common stock. Any price adjustment we would have been required to pay would have been settled in either cash or common stock at our option. The final price adjustment settlement, along with the delivery of the remaining shares, occurred in April 2022, resulting in the delivery to us of 0.4 million additional shares. In total, we repurchased 1.7 million shares pursuant to the February 2022 accelerated share repurchase agreement. During the year ended December 31, 2022, we repurchased 4.0 million shares in open market transactions at a cost of $150.1 million. In November 2021, we entered into an accelerated repurchase agreement with terms similar to the previously discussed February 2022 accelerated share repurchase agreement. Pursuant to this agreement, we paid $50.0 million to a financial counterparty and received an initial delivery of 1.4 million shares of our common stock. We simultaneously entered into a forward contract indexed to the price of Unum Group common stock, which resulted in the delivery to us of 0.5 million additional shares also in November 2021. In total, we repurchased 1.9 million shares pursuant to the accelerated repurchase agreement. During 2021, there were no shares repurchased in open market transactions. Preferred Stock Unum Group has 25.0 million shares of preferred stock authorized with a par value of $0.10 per share. No preferred stock has been issued to date.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments	Description of Stock Plans Under the 2022 Stock Incentive Plan (the 2022 Plan), up to 6.8 million shares of common stock are available for awards to our employees, officers, consultants, and directors. Awards may be in the form of stock options, stock appreciation rights, restricted stock, restricted stock units, performance share units, and other stock-based awards. Each award, under the 2022 plan is counted as 1.00 share. The exercise price for stock options issued cannot be less than the fair value of the underlying common stock as of the grant date. The maximum term of each stock option or stock appreciation right is ten years after the date of grant. At December 31, 2022, approximately 6.6 million shares were available for future grants under the 2022 Plan. Under the Stock Incentive Plan of 2017 (the 2017 Plan), which was terminated in May 2022 for the purposes of any further grants, up to 17.0 million shares of common stock were available for awards to our employees, officers, consultants, and directors. Awards could be in the form of stock options, stock appreciation rights, restricted stock, restricted stock units, performance share units, and other stock-based awards. Each full-value award under the 2017 plan, defined as any award other than a stock option or stock appreciation right, were counted as 1.76 shares. Awards granted before the termination of the 2017 Plan remain outstanding in accordance with the plan's terms. Any shares subject to an outstanding award under the 2017 Plan that, after March 15, 2022, is not issued because the award is forfeited, terminates, expires or lapses without being exercised (as applicable), or is settled for cash, will become available for issuance under the 2022 Plan. Stock options had a term of eight We issue new shares of common stock for all of our stock plan vestings and exercises. Stock Success Units (SSUs) SSUs are classified as equity. As of both December 31, 2022 and 2021, there were 208 thousand shares of SSUs outstanding with a weighted average grant date fair value of $18.78 per share. There were no issuances of SSUs during 2022 or 2021. During 2020, we issued SSUs with a weighted average grant date fair value per share of $18.78. SSUs vest over a six No SSUs vested or were forfeited during 2022. The total fair value of SSUs that vested during 2021 was $1.9 million. No SSUs vested during 2020. At December 31, 2022, we had $1.7 million of unrecognized compensation cost related to SSUs that will be recognized over a remaining weighted average period of 1.2 years. Performance Share Units (PSUs) PSUs are classified as equity. There were no new issuances of PSUs during 2022 or 2021. During 2020, we issued PSUs with a weighted average grant date fair value per share of $23.49. Vesting for the PSUs occurred at the end of a three-year period and was contingent upon our achievement of prospective company performance goals and our total shareholder return relative to a board-approved peer group during the three We had no outstanding PSUs at December 31, 2022. We had 308 thousand PSUs outstanding at December 31, 2021 with a weighted average grant date fair value of $23.58 per share. There was a decrease of 75 thousand shares granted during 2022 with a weighted average grant date fair value of $40.67 per share, which reflects the application of the performance factor to the 2019 PSU grant that was less than 100 percent. 256 thousand shares vested during 2022 with a weighted average grant date fair value of $16.29 per share. Included in the 2022 vested amount is the application of the performance factor to the 2019 PSU grant, which occurred during the first quarter of 2022. There were 2 thousand shares forfeited during 2022 with a weighted average grant date fair value of $23.58 per share. PSU shares represent aggregate initial target awards and accrued dividend equivalents and do not reflect potential increases or decreases resulting from the application of the performance factor determined after the end of the performance periods. At December 31, 2022, the three The total fair value of shares vested during 2022, 2021, and 2020 was $4.2 million, $6.6 million, and $6.5 million, respectively. At December 31, 2022, we had no unrecognized compensation cost related to PSUs as there are no remaining PSUs outstanding. The estimated compensation expense was adjusted for actual performance experience and was recognized ratably during the service period when it became probable that the performance conditions would be satisfied. Compensation cost for PSUs subject to accelerated vesting at the date of retirement eligibility was recognized over the implicit service period. The fair value of PSUs is estimated on the date of initial grant using the Monte-Carlo simulation m odel. Key assumptions used to value PSUs granted during 2020 are as follows: Year Ended December 31, 2020 Expected Volatility (based on our and our peer group historical daily stock prices) 23 % Expected Life (equals the performance period) 3 years Risk Free Interest Rate (based on U.S. Treasury yields at the date of grant) 0.85 % Cash Incentive Units (CIUs) Activity for CIUs classified as a liability is as follows: Weighted Average Units Grant Date (000s) Fair Value Outstanding at December 31, 2021 7,223 $ 1.07 Granted 8,024 1.09 Outstanding at December 31, 2022 15,247 1.08 During 2022 and 2021, we issued CIUs with a weighted average grant date fair value per unit of $1.09 and $1.07, respectively. During 2020, no CIUs were issued. CIUs are denominated and settled in cash. Vesting for the CIUs occurs at the end of a three-year period and is based upon prospective company performance measures and our total shareholder return relative to a board-approved peer group during the three CIUs in the preceding table represent aggregate initial target awards and do not reflect potential increases or decreases resulting from the application of the performance factor determined after the end of the performance periods. No CIUs have vested as of December 31, 2022. At December 31, 2022, we had approximately $9.6 million of unrecognized compensation cost related to CIUs that will be recognized over a weighted average period of one year. The estimated compensation expense is adjusted for actual performance experience and is recognized ratably during the service period, or remaining service period, if and when it becomes probable that the performance conditions will be satisfied. Compensation cost for CIUs subject to accelerated vesting at the date of retirement eligibility is recognized over the implicit service period. The fair value of CIUs is estimated at each reporting period using the Monte-Carlo simulation m odel. Key assumptions used to value CIUs granted during current year are as follows: Year Ended December 31 2022 2021 Expected Volatility (based on our and our peer group historical daily stock prices) 30 % 50 % Expected Life (equals the performance period) 3 years 3 years Risk Free Interest Rate (based on U.S. Treasury yields at the date of grant) 4.26 % 0.71 % Restricted Stock Units (RSUs) Activity for RSUs classified as equity is as follows: Weighted Average Shares Grant Date (000s) Fair Value Outstanding at December 31, 2021 2,016 $ 26.63 Granted 1,323 28.21 Vested (1,018) 27.51 Forfeited (139) 26.19 Outstanding at December 31, 2022 2,182 27.20 During 2022, 2021, and 2020, we issued RSUs with a weighted average grant date fair value per share of $28.21, $27.02, and $22.71, respectively. RSUs vest over a one three Compensation cost for RSUs subject to accelerated vesting at the date of retirement eligibility is recognized over the implicit service period. The total fair value of shares vested during 2022, 2021, and 2020 was $28.0 million, $23.9 million, and $25.1 million, respectively. At December 31, 2022, we had $31.9 million of unrecognized compensation cost related to RSUs that will be recognized over a weighted average period of 0.8 years. Cash-Settled RSUs Activity for cash-settled RSUs classified as a liability is as follows: Weighted Average Shares Grant Date (000s) Fair Value Outstanding at December 31, 2021 46 $ 23.31 Vested (23) 23.31 Outstanding at December 31, 2022 23 23.31 During 2020, we issued cash-settled RSUs with a weighted average grant date fair value per share of $22.94. There were no issuances of cash-settled RSUs during 2022 or 2021. Cash-settled RSUs vest over a one three The amount payable per unit awarded is equal to the price per share of Unum Group's common stock at settlement of the award, and as such, we measure the value of the award each reporting period based on the current stock price. The effects of changes in the stock price during the service period are recognized as compensation cost over the service period. Changes in the amount of the liability due to stock price changes after the service period are recognized as compensation cost during the period in which the changes occur. At December 31, 2022, we had $0.2 million of unrecognized compensation cost related to cash-settled RSUs that will be recognized over a weighted average period of 0.1 years. Stock Options There were no stock options granted or vested in the years 2020 through 2022. There were no options exercised in 2022, and the intrinsic value of options exercised in both 2021 and 2020 was $0.1 million. As of December 31, 2021, we have no unrecognized compensation cost related to stock options as there are no exercisable stock options outstanding. Stock options vested over a one three Expense Compensation expense for the stock based plans, as reported in our consolidated statements of income, is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Performance Share Units $ 5.7 $ 3.3 $ 5.6 Cash Incentive Units 12.8 3.2 — Restricted Stock Units and Cash-Settled Restricted Stock Units 32.7 25.5 23.9 Stock Success Units 0.9 2.8 0.4 Other 0.6 0.6 0.5 Total Compensation Expense, Before Income Tax $ 52.7 $ 35.4 $ 30.4 Total Compensation Expense, Net of Income Tax $ 47.3 $ 31.1 $ 26.1

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2022
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance activity related to both our premium income and changes in reserves for future benefits are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Direct Premium Income $ 9,900.5 $ 9,742.8 $ 9,621.9 Reinsurance Assumed 78.7 90.6 94.1 Reinsurance Ceded (355.8) (352.4) (337.9) Net Premium Income $ 9,623.4 $ 9,481.0 $ 9,378.1 Ceded Benefits and Change in Reserves for Future Benefits $ 1,034.6 $ 862.5 $ 628.8 In December 2020, Provident, The Paul Revere Life Insurance Company (Paul Revere Life), and Unum America, wholly-owned domestic insurance subsidiaries of Unum Group and collectively referred to as "the ceding companies", each entered into separate reinsurance agreements with Commonwealth Annuity and Life Insurance Company (Commonwealth), to reinsure on a coinsurance basis effective as of July 1, 2020 approximately 75 percent of the Closed Block individual disability business, primarily direct business written by the ceding companies. In March 2021, we completed the second phase of the reinsurance transaction, pursuant to which the ceding companies and Commonwealth amended and restated their respective reinsurance agreements to reinsure on a coinsurance and modified coinsurance basis effective as of January 1, 2021, a substantial portion of the remaining Closed Block individual disability business that was not ceded in December 2020, primarily business previously assumed by the ceding companies. Commonwealth has established and will maintain collateralized trust accounts for the benefit of the ceding companies to secure its obligations under the relevant reinsurance agreement. In connection with the first phase of the reinsurance transaction which occurred in December 2020, the ceding companies paid a total ceding commission to Commonwealth of $437.7 million and transferred additional assets consisting primarily of fixed maturity securities and cash totaling $6,669.8 million. In connection with the second phase of the reinsurance transaction which occurred in March 2021, Commonwealth paid a total ceding commission to the ceding companies of $18.2 million. Also in connection with the second phase, the ceding companies transferred additional assets consisting primarily of fixed maturity securities and cash to Commonwealth of $767.0 million. In December 2020, Provident Life and Casualty Insurance Company (PLC), also a wholly-owned domestic insurance subsidiary of Unum Group, entered into an agreement with Commonwealth whereby PLC will provide a 12-year volatility cover to Commonwealth for the active life cohort (ALR cohort). As part of this agreement, PLC received a payment from Commonwealth of approximately $62 million. In March 2021, PLC and Commonwealth amended and restated this agreement to incorporate the ALR cohort related to the additional business that was reinsured between the ceding companies and Commonwealth as part of the second phase of the transaction. As part of the amended and restated volatility cover, PLC received a payment from Commonwealth of approximately $18 million. At the end of the 12-year coverage period in 2032, Commonwealth will retain the remaining incidence and claims risk on the ALR cohort of the ceded business. Under this volatility cover, annual settlements will be made equal to the difference between the actual and estimated cash flows and reserve changes during the year. Upon expiration of the 12-year period, a terminal settlement will be made based on the final disabled life reserves. As a result of the volatility cover, the reinsurance agreement covering the ALR cohort does not pass risk transfer requirements under GAAP and is accounted for under the deposit method. As a result of the reinsurance transaction, we recognized the following items for the first phase in December 2020 and the second phase in March 2021, respectively: • Net realized investment gains totaling $1,302.3 million and $67.6 million related to the transfer of investments. • Increase in benefits and change in reserves for future benefits of $1,284.5 million and $133.1 million resulting from the realization of previously unrealized investment gains and losses recorded in accumulated other comprehensive income. • Transaction costs totaling $21.0 million and $6.2 million. • Reinsurance recoverable of $6,141.5 million and $990.0 million related to the policies on claim status (DLR cohort). • Cost of reinsurance, or prepaid reinsurance premium, of $815.7 million and $43.1 million related to the DLR cohort. • Deposit asset of $88.2 million and $5.0 million related to the ALR cohort. • Tax benefit of $36.5 million, in connection with the first phase. • Payable of $307.2 million related to the portfolio of invested assets associated with the business ceded on a modified coinsurance basis, in connection with the second phase. The cost of reinsurance is amortized over the expected run-off pattern of the ceded reserves for the DLR cohort and we recognized $63.8 million, $79.1 million, and $2.6 million in amortization expense for 2022, 2021, and 2020, respectively. The deposit asset is adjusted over the 12-year period of the volatility cover based on cash flows related to the ALR cohort, settlement payments as determined above, and accretion of interest and will result in an amount equal to the expected disabled life reserve for the ALR cohort at the expiration of the volatility cover. Both the cost of reinsurance and the deposit asset are reported in Other Assets within our Consolidated Balance Sheets. As of December 31, 2022, Commonwealth accounted for 59 percent of the total reinsurance recoverable and the majority of our total cost of reinsurance. Commonwealth has an A rating by A.M. Best Company (AM Best) and has also established collateralized trust accounts for our benefit to secure its obligations. In addition, nine other major companies, which account for approximately 36 percent of our reinsurance recoverable, are also rated A or better by either AM Best or Standard & Poor's Ratings Services (S&P), or are fully securitized by letters of credit or investment-grade fixed maturity securities held in trust. Approximately 4 percent of our reinsurance recoverable is primarily related to business reinsured with other companies also rated A- or better by AM Best or S&P, with overseas entities with equivalent ratings, or backed by letters of credit or trust agreements, or through reinsurance arrangements wherein we retain the assets in our general account. Less than one percent of our reinsurance recoverable is held by companies either rated below A- by AM Best or S&P, or not rated.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2022
Segment Reporting [Abstract]
Segment Information	We have three principal operating business segments: Unum US, Unum International, and Colonial Life. Our other segments are Closed Block and Corporate. The Unum US segment is comprised of group disability, group life and accidental death and dismemberment, and supplemental and voluntary lines of business. The group disability line of business includes long-term and short-term disability, medical stop-loss, and fee-based service products. The supplemental and voluntary line of business includes voluntary benefits, individual disability, and dental and vision products. These products are marketed through our field sales personnel who work in conjunction with independent brokers and consultants. The Unum International segment is comprised of our operations in both the United Kingdom and Poland. Our Unum UK products include insurance for group long-term disability, group life, and supplemental lines of business which include dental, individual disability, and critical illness products. Our Unum Poland products include insurance for individual and group life with accident and health riders. Unum International's products are sold primarily through field sales personnel and independent brokers and consultants. The Colonial Life segment includes insurance for accident, sickness, and disability products, which includes our dental and vision products, life products, and cancer and critical illness products marketed to employees, on both a group and an individual basis, at the workplace through an independent contractor agent sales force and brokers. The Closed Block segment consists of group and individual long-term care, and other insurance products no longer actively marketed. We discontinued offering individual long-term care in 2009 and group long-term care in 2012. Other insurance products include individual disability, group pension, individual life and corporate-owned life insurance, reinsurance pools and management operations, and other miscellaneous product lines. In December 2020, we entered into the first phase of a reinsurance agreement to reinsure the majority of our Closed Block individual disability products to a third party. In March 2021, we completed the second phase of the reinsurance transaction to reinsure a portion of the remaining Closed Block individual disability business that was not ceded in December 2020. See Note 12 for further discussion. The Corporate segment includes investment income on corporate assets not specifically allocated to a line of business, interest expense on corporate debt, and certain other corporate income and expenses not allocated to a line of business. Impairment Loss on Internal-Use Software During 2021, we recognized an impairment loss of $12.1 million for previously capitalized internal-use software that we no longer plan to utilize. We determined that this internal-use software would no longer be developed in order to focus our efforts on the development of software that better supports our long-term strategic goals. The impairment loss reduced the carrying value of the internal-use software to zero and has been recorded within other expenses in the consolidated statements of income and is included within our Corporate segment. Costs Related to Organizational Design Update During 2020, we realigned certain parts of our organizational structure by shifting resources to accelerate growth, fund priority investments, and simplify and improve our business practices. In connection with this update, we incurred charges of $23.3 million, which primarily consisted of employee severance and benefit costs as well as certain costs related to lease terminations and the disposal of certain fixed assets. These costs were recorded within either compensation expense or other expenses in the consolidated statements of income and were included within our Corporate segment. This update did not result in the exit or disposal of any of our lines of business. Segment information is shown below. Certain prior year amounts were reclassified to conform to current year presentation. Year Ended December 31 2022 2021 2020 (in millions of dollars) Premium Income Unum US Group Disability Group Long-term Disability $ 1,911.7 $ 1,827.8 $ 1,828.5 Group Short-term Disability 926.3 864.0 799.2 Group Life and Accidental Death & Dismemberment Group Life 1,669.1 1,641.9 1,640.5 Accidental Death & Dismemberment 173.7 165.1 163.9 Supplemental and Voluntary Voluntary Benefits 840.6 846.7 875.2 Individual Disability 461.1 459.8 456.0 Dental and Vision 275.8 272.7 255.6 6,258.3 6,078.0 6,018.9 Unum International Unum UK Group Long-term Disability 376.9 401.9 364.9 Group Life 138.2 112.3 108.5 Supplemental 114.0 112.6 99.8 Unum Poland 89.7 90.2 79.6 718.8 717.0 652.8 Colonial Life Accident, Sickness, and Disability 948.9 953.3 975.1 Life 401.1 384.7 376.4 Cancer and Critical Illness 352.0 352.2 360.5 1,702.0 1,690.2 1,712.0 Closed Block Long-term Care 697.4 704.3 666.9 All Other 246.9 291.5 327.5 944.3 995.8 994.4 Total Premium Income $ 9,623.4 $ 9,481.0 $ 9,378.1 Unum US Unum International Colonial Life Closed Block Corporate Total (in millions of dollars) Year Ended December 31, 2022 Premium Income $ 6,258.3 $ 718.8 $ 1,702.0 $ 944.3 $ — $ 9,623.4 Net Investment Income 676.3 170.1 152.7 1,070.6 52.5 2,122.2 Other Income 196.3 0.9 1.1 58.0 4.8 261.1 Adjusted Operating Revenue $ 7,130.9 $ 889.8 $ 1,855.8 $ 2,072.9 $ 57.3 $ 12,006.7 Adjusted Operating Income (Loss) $ 970.7 $ 127.0 $ 374.6 $ 247.9 $ (164.3) $ 1,555.9 Interest and Debt Expense $ — $ — $ — $ — $ 192.7 $ 192.7 Depreciation and Amortization $ 370.6 $ 22.0 $ 303.5 $ 4.7 $ 0.6 $ 701.4 Year Ended December 31, 2021 Premium Income $ 6,078.0 $ 717.0 $ 1,690.2 $ 995.8 $ — $ 9,481.0 Net Investment Income 721.6 132.7 172.0 1,159.0 27.9 2,213.2 Other Income 170.0 0.6 1.0 65.1 6.2 242.9 Adjusted Operating Revenue $ 6,969.6 $ 850.3 $ 1,863.2 $ 2,219.9 $ 34.1 $ 11,937.1 Adjusted Operating Income (Loss) $ 464.9 $ 105.7 $ 329.2 $ 394.7 $ (177.9) $ 1,116.6 Interest and Debt Expense $ — $ — $ — $ — $ 185.0 $ 185.0 Depreciation and Amortization $ 400.9 $ 21.0 $ 275.4 $ 5.1 $ 0.7 $ 703.1 Year Ended December 31, 2020 Premium Income $ 6,018.9 $ 652.8 $ 1,712.0 $ 994.4 $ — $ 9,378.1 Net Investment Income 720.3 104.6 155.7 1,370.3 9.8 2,360.7 Other Income 154.9 0.5 1.1 66.6 1.1 224.2 Adjusted Operating Revenue $ 6,894.1 $ 757.9 $ 1,868.8 $ 2,431.3 $ 10.9 $ 11,963.0 Adjusted Operating Income (Loss) $ 825.4 $ 76.6 $ 335.4 $ 241.4 $ (200.8) $ 1,278.0 Interest and Debt Expense $ — $ — $ — $ 3.1 $ 185.1 $ 188.2 Depreciation and Amortization $ 421.7 $ 20.1 $ 273.9 $ 5.9 $ 0.7 $ 722.3 Unum Colonial Unum US International Life Total (in millions of dollars) Deferred Acquisition Costs Year Ended December 31, 2022 Beginning of Year $ 1,096.2 $ 35.4 $ 1,076.3 $ 2,207.9 Capitalization 273.1 12.0 271.8 556.9 Amortization (294.9) (7.6) (288.5) (591.0) Adjustment Related to Unrealized Investment Gains and Losses 15.0 — 66.7 81.7 Foreign Currency — (3.2) — (3.2) End of Year $ 1,089.4 $ 36.6 $ 1,126.3 $ 2,252.3 Year Ended December 31, 2021 Beginning of Year $ 1,168.7 $ 32.0 $ 1,071.9 $ 2,272.6 Capitalization 242.7 12.8 252.6 508.1 Amortization (319.0) (8.0) (259.1) (586.1) Adjustment Related to Unrealized Investment Gains and Losses 3.8 — 10.9 14.7 Foreign Currency — (1.4) — (1.4) End of Year $ 1,096.2 $ 35.4 $ 1,076.3 $ 2,207.9 Year Ended December 31, 2020 Beginning of Year $ 1,223.0 $ 26.4 $ 1,074.6 $ 2,324.0 Capitalization 291.5 12.1 272.6 576.2 Amortization (341.0) (7.4) (257.7) (606.1) Adjustment Related to Unrealized Investment Gains and Losses (4.8) — (17.6) (22.4) Foreign Currency — 0.9 — 0.9 End of Year $ 1,168.7 $ 32.0 $ 1,071.9 $ 2,272.6 December 31 2022 2021 (in millions of dollars) Assets Unum US $ 16,278.7 $ 18,696.3 Unum International 3,154.9 4,086.5 Colonial Life 4,448.9 4,895.9 Closed Block 34,241.2 38,287.9 Corporate 3,311.2 4,149.0 Total Assets $ 61,434.9 $ 70,115.6 Revenue is primarily derived from sources in the United States, the United Kingdom, and Poland. There are no material revenues or assets attributable to foreign operations other than those reported in our Unum International segment. We report goodwill in our Unum US, Unum International, and Colonial Life segments, which are the segments expected to benefit from the originating business combinations. At December 31, 2022 and 2021 goodwill was $347.6 million and $352.2 million, respectively, with $280.0 million attributable to Unum US in each year, $39.9 million and $44.5 million, respectively, attributable to Unum International, and $27.7 million attributable to Colonial Life in each year. Stockholders' equity is allocated to the operating segments on the basis of an internal allocation formula that reflects the volume and risk components of each operating segment's business and aligns allocated equity with our target capital levels for regulatory and rating agency purposes. We modify this formula periodically to recognize changes in the views of capital requirements. We measure and analyze our segment performance on the basis of "adjusted operating revenue" and "adjusted operating income" or "adjusted operating loss", which differ from total revenue and income before income tax as presented in our consolidated statements of income due to the exclusion of investment gains and losses and the amortization of the cost of reinsurance as well as other items specified in the reconciliations below. We believe adjusted operating revenue and adjusted operating income or loss are better performance measures and better indicators of the revenue and profitability and underlying trends in our business. These performance measures are in accordance with GAAP guidance for segment reporting, but they should not be viewed as a substitute for total revenue, income before income tax, or net income. Investment gains or losses primarily include realized investment gains or losses, expected investment credit losses, and gains or losses on derivatives. Investment gains or losses depend on market conditions and do not necessarily relate to decisions regarding the underlying business of our segments. Our investment focus is on investment income to support our insurance liabilities as opposed to the generation of investment gains or losses. Although we may experience investment gains or losses which will affect future earnings levels, a long-term focus is necessary to maintain profitability over the life of the business since our underlying business is long-term in nature, and we need to earn the interest rates assumed in calculating our liabilities. As previously discussed in Note 12, we have exited a substantial portion of our Closed Block individual disability product line through the two phases of the reinsurance transaction that were executed in December 2020 and March 2021. As a result, we exclude the amortization of the cost of reinsurance that was recognized upon the exit of the business related to the DLR cohort of policies. We believe that the exclusion of the amortization of the cost of reinsurance provides a better view of our results from our ongoing businesses. We may, at other times, exclude certain other items from our discussion of financial ratios and metrics in order to enhance the understanding and comparability of our operational performance and the underlying fundamentals but this exclusion is not an indication that similar items may not recur and does not replace net income or net loss as a measure of our overall profitability. See above and Notes 3, 6, 8, 12, and 15 for further discussion regarding the items specified in the reconciliation below. A reconciliation of total revenue to "adjusted operating revenue" and income before income tax to "adjusted operating income" is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Total Revenue $ 11,991.0 $ 12,013.8 $ 13,162.1 Excluding: Net Investment Gain (Loss) (15.7) 76.7 1,199.1 Adjusted Operating Revenue $ 12,006.7 $ 11,937.1 $ 11,963.0 Income Before Income Tax $ 1,631.4 $ 1,063.0 $ 964.0 Excluding: Net Investment Gains and Losses Net Realized Investment Gain Related to Reinsurance Transaction — 67.6 1,302.3 Net Investment Gain (Loss), Other (15.7) 9.1 (103.2) Total Net Investment Gain (Loss) (15.7) 76.7 1,199.1 Items Related to Closed Block Individual Disability Reinsurance Transaction Change in Benefit Reserves and Transaction Costs — (139.3) (1,305.5) Amortization of the Cost of Reinsurance (63.8) (79.1) (2.6) Total Items Related to Closed Block Individual Disability Reinsurance Transaction (63.8) (218.4) (1,308.1) Net Reserve Change Related to Reserve Assumption Updates 155.0 181.4 (169.0) Impairment Loss on Internal-Use Software — (12.1) — Cost Related to Early Retirement of Debt — (67.3) — Impairment Loss on ROU Asset — (13.9) (12.7) Costs Related to Organizational Design Update — — (23.3) Adjusted Operating Income $ 1,555.9 $ 1,116.6 $ 1,278.0

Commitments and Contingent Liab

Commitments and Contingent Liabilities	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure	Commitments See Notes 2 and 3 for further discussion on certain investment commitments of the Company. Contingent Liabilities We are a defendant in a number of litigation matters that have arisen in the normal course of business, including the matters discussed below. Further, state insurance regulatory authorities and other federal and state authorities regularly make inquiries and conduct investigations concerning our compliance with applicable insurance and other laws and regulations. Given the complexity and scope of our litigation and regulatory matters, it is not possible to predict the ultimate outcome of all pending investigations or legal proceedings or provide reasonable estimates of potential losses, except if noted in connection with specific matters. In some of these matters, no specified amount is sought. In others, very large or indeterminate amounts, including punitive and treble damages, are asserted. There is a wide variation of pleading practice permitted in the United States courts with respect to requests for monetary damages, including some courts in which no specified amount is required and others which allow the plaintiff to state only that the amount sought is sufficient to invoke the jurisdiction of that court. Further, some jurisdictions permit plaintiffs to allege damages well in excess of reasonably possible verdicts. Based on our extensive experience and that of others in the industry with respect to litigating or resolving claims through settlement over an extended period of time, we believe that the monetary damages asserted in a lawsuit or claim bear little relation to the merits of the case, or the likely disposition value. Therefore, the specific monetary relief sought is not stated. Unless indicated otherwise in the descriptions below, reserves have not been established for litigation and contingencies. An estimated loss is accrued when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Claims Handling Matters We and our insurance subsidiaries, in the ordinary course of our business, are engaged in claim litigation where disputes arise as a result of a denial or termination of benefits. Most typically these lawsuits are filed on behalf of a single claimant or policyholder, and in some of these individual actions punitive damages are sought, such as claims alleging bad faith in the handling of insurance claims. For our general claim litigation, we maintain reserves based on experience to satisfy judgments and settlements in the normal course. We expect that the ultimate liability, if any, with respect to general claim litigation, after consideration of the reserves maintained, will not be material to our consolidated financial condition. Nevertheless, given the inherent unpredictability of litigation, it is possible that an adverse outcome in certain claim litigation involving punitive damages could, from time to time, have a material adverse effect on our consolidated results of operations in a period, depending on the results of operations for the particular period. From time to time class action allegations are pursued where the claimant or policyholder purports to represent a larger number of individuals who are similarly situated. Since each insurance claim is evaluated based on its own merits, there is rarely a single act or series of actions which can properly be addressed by a class action. Nevertheless, we monitor these cases closely and defend ourselves appropriately where these allegations are made.

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Lessee, Operating Leases	We lease certain buildings and equipment under various noncancellable operating lease agreements. In addition, we have sub-lease agreements on a limited number of our building lease agreements. We generally have the option to renew the majority of our building leases and equipment leases at the end of the lease term at the fair rental value at the time of renewal. We do not have any lease agreements or sub-lease agreements that contain variable lease payments. In addition, we do not have lease agreements or sub-lease agreements that contain residual value guarantees or impose any financial restrictions or covenants with the lessors. Operating lease information is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Lease Cost Operating Lease Cost $ 19.6 $ 35.2 $ 48.6 Sublease Income (1.1) (1.0) (1.3) Total Lease Cost $ 18.5 $ 34.2 $ 47.3 Other Information Cash Paid for Amounts Included in the Measurement of Lease Liabilities $ 23.1 $ 29.9 $ 30.8 Weighted-Average Remaining Lease Term 6 years 6 years 6 years Weighted-Average Discount Rate 4.32 % 4.45 % 4.37 % As of December 31, 2022, aggregate undiscounted minimum lease payments and the reconciliation to our lease liability are as follows (in millions of dollars): 2023 $ 18.2 2024 14.4 2025 11.1 2026 9.1 2027 8.3 2028 and Thereafter 17.4 Total 78.5 Less Imputed Interest 10.6 Lease Liability $ 67.9 The right-of-use asset was $ 37.7 49.1 During 2021 and 2020, we recognized impairment losses of $13.9 million and $12.7 million, respectively, on the ROU asset related to one of our operating leases for office space that we do not plan to continue using to support our general operations. The impairment losses were recorded as a result of a decrease in the fair value of the ROU asset compared to its carrying value. The fair value of the ROU asset was determined based on a discounted cash flow model utilizing estimated market rates for sub-lease rentals. The impairment losses for each period are recorded within other expenses in the consolidated statements of income and are included within our Corporate segment.

Statutory Financial Information

Statutory Financial Information	12 Months Ended
	Dec. 31, 2022
Statutory Financial Information [Abstract]
Statutory Financial Information	Statutory Net Income, Capital and Surplus, and Dividends Statutory net income for U.S. life insurance companies is reported in conformity with statutory accounting principles prescribed by the National Association of Insurance Commissioners (NAIC) and adopted by applicable domiciliary state laws. The commissioners of the states of domicile have the right to permit other specific practices that may deviate from prescribed practices. In connection with a financial examination of Unum America, which closed at the end of the second quarter of 2020, the Maine Bureau of Insurance (MBOI) concluded that Unum America’s long-term care statutory reserves were deficient by $2,100.0 million as of December 31, 2018, the financial statement date of the examination period. The amount reserves are deficient may increase or decrease over time based on changes in assumed reinvestment rates, policyholder inventories, rate increase activity, and the underlying growth in the locked in statutory reserve basis as well as updates to other long term actuarial assumptions. The MBOI granted permission to Unum America on May 1, 2020, to phase in the additional statutory reserves over seven years beginning with year-end 2020 and ending with year-end 2026. Additional information regarding the Unum America premium deficiency reserve (PDR) is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Premium Deficiency Reserve Gross Premium Deficiency Reserve 1 $ 2,851.0 $ 2,977.0 $ 2,290.0 Cumulative Gross Premium Deficiency Reserve Recognized 1,191.0 667.0 229.0 Remaining Premium Deficiency Reserve to be Recognized $ 1,660.0 $ 2,310.0 $ 2,061.0 1 The gross PDR decreased by $126.0 million due primarily to premium rate increase activity and underlying growth in the locked-in statutory reserve basis during 2022. The gross PDR increased by $687.0 million and $190.0 million during 2021 and 2020, respectively, due primarily to changes in the assumed reinvestment rate. The increase for 2020 was from the original $2,100.0 million reserve deficiency as of December 31, 2018. The phase in amounts for 2022, 2021, and 2020 were funded using cash flows from operations and capital contributions from Unum Group. This strengthening is incorporated by using explicitly agreed upon margins into our existing assumptions for annual statutory reserve adequacy testing. These actions add margin to Unum America's best estimate assumptions. Our long-term care reserves and financial results reported under generally accepted accounting principles are not affected by the MBOI’s examination conclusion. We plan to fund the additional statutory reserves with expected cash flows and capital contributions from Unum Group. If the permitted practice was not granted by the MBOI to phase in these additional statutory reserves, the impact to the risk-based capital ratio would have triggered a regulatory event. Our other traditional U.S. life insurance subsidiaries have no prescribed or permitted statutory accounting practices that differ materially from statutory accounting principles prescribed by the NAIC. Unum America cedes certain blocks of business to Fairwind Insurance Company (Fairwind), which is an affiliated captive reinsurance subsidiary (captive reinsurer) domiciled in the United States, with Unum Group as the ultimate parent. This captive reinsurer was established for the limited purpose of reinsuring risks attributable to specified policies issued or reinsured by Unum America. Fairwind, which is domiciled in the state of Vermont, is required to follow GAAP in accordance with Vermont reporting requirements for pure captive insurance companies, unless the commissioner permits the use of some other basis of accounting. Fairwind has permission from Vermont to follow accounting practices that are generally consistent with current NAIC statutory accounting principles for its insurance reserves and invested assets supporting reserves. All other assets and liabilities are accounted for in accordance with GAAP, as prescribed by Vermont, which includes the full recognition of deferred tax assets which are more likely than not to be realized. Statutory accounting principles have a stricter limitation for the recognition of deferred tax assets. The impact of following the prescribed and permitted practices of Vermont rather than statutory accounting principles prescribed by the NAIC resulted in higher capital and surplus for Fairwind of approximately $351 million and $360 million as of December 31, 2022 and 2021 respectively. The 2022, 2021, and 2020 results for Fairwind include the $524.0 million, $438 million, and $229 million increases to long-term care statutory reserves assumed from Unum America. In December 2020, prior to entering into the reinsurance transaction with Commonwealth, Provident, Paul Revere Life, and Unum America recaptured their respective reinsurance agreements with Northwind Reinsurance Company (Northwind Re), a wholly-owned domestic special purpose reinsurance subsidiary. See Note 12 for further discussion regarding the reinsurance transaction with Commonwealth. Northwind Re was established for the limited purpose of reinsuring risks attributable to specified policies issued or reinsured by the aforementioned companies, and had no material state prescribed accounting practices that differ from statutory accounting principles prescribed by the NAIC. As a result of the recapture of the reinsurance agreements during 2020, no insurance risk remained in Northwind Re. In 2021, Northwind Re obtained a Certificate of Dormancy from the Vermont Department of Financial Regulation authorizing it to exist as a dormant captive insurance company, leaving Fairwind as the only remaining active captive reinsurer. During 2022, Northwind Re was merged with one of our non-insurance U.S. holding companies, Northwind Holdings, with Northwind Holdings remaining as the surviving company. Subsequently during 2022, Northwind Holdings was merged into Unum Group. The operating results and capital and surplus of our traditional U.S. life insurance subsidiaries and our captive reinsurers, prepared in accordance with prescribed or permitted accounting practices of the NAIC or states of domicile, are presented separately below. Year Ended December 31 2022 2021 2020 (in millions of dollars) Combined Net Income (Loss) Traditional U.S. Life Insurance Subsidiaries $ 965.4 $ 779.5 $ 646.8 Captive Reinsurers $ (432.2) $ (159.0) $ (201.0) Combined Net Gain (Loss) from Operations, After Tax Traditional U.S. Life Insurance Subsidiaries $ 965.4 $ 681.1 $ 726.2 Captive Reinsurers $ (428.6) $ (247.4) $ (149.4) December 31 2022 2021 (in millions of dollars) Combined Capital and Surplus Traditional U.S. Life Insurance Subsidiaries $ 3,816.3 $ 3,950.3 Captive Reinsurers $ 1,229.6 $ 1,258.4 Solvency II, an European Union directive that is part of retained U.K. law pursuant to the European Union (Withdrawal) Act 2018, prescribes capital requirements and risk management standards for the European insurance industry. As derived from the most recent annual financial statements for December 31, 2021, based on Solvency II requirements, regulatory net gain and own funds available of our United Kingdom insurance subsidiary, Unum Limited, were £121.8 million and £631.0 million, respectively. Risk-based capital (RBC) standards for U.S. life insurance companies are prescribed by the NAIC. The domiciliary states of our U.S. insurance subsidiaries have all adopted a version of the RBC model formula of the NAIC, which prescribes a system for assessing the adequacy of statutory capital and surplus for all life and health insurers. The basis of the system is a risk-based formula that applies prescribed factors to the various risk elements in a life and health insurer's business to report a minimum capital requirement proportional to the amount of risk assumed by the insurer. The life and health RBC formula is designed to measure annually (i) the risk of loss from asset defaults and asset value fluctuations, (ii) the risk of loss from adverse mortality and morbidity experience, (iii) the risk of loss from mismatching of asset and liability cash flow due to changing interest rates, and (iv) business risks. The formula is used as an early warning tool to identify companies that are potentially inadequately capitalized. State insurance laws grant insurance regulators the authority to require various actions by, or take various actions against, insurers whose total adjusted capital does not meet or exceed certain RBC levels. The total adjusted capital of each of our U.S. insurance subsidiaries at December 31, 2022 is in excess of those RBC levels. Restrictions under applicable state insurance laws limit the amount of dividends that can be paid to a parent company from its insurance subsidiaries in any 12-month period without prior approval by regulatory authorities. For life insurance companies domiciled in the U.S., that limitation generally equals, depending on the state of domicile, either ten percent of an insurer's statutory surplus with respect to policyholders as of the preceding year end or the statutory net gain from operations, excluding net realized capital gains and losses, of the preceding year. The payment of dividends to a parent company from a life insurance subsidiary is generally further limited to the amount of unassigned funds. Based on the restrictions under current law, approximately $991 million is available, without prior approval by regulatory authorities, during 2023 for the payment of dividends to Unum Group from its traditional U.S. life insurance subsidiaries. The ability of our captive insurer to pay dividends to Unum Group will depend on the satisfaction of applicable regulatory requirements and on the performance of the business reinsured by Fairwind. We also have the ability to receive dividends from our foreign subsidiaries, primarily in the U.K., for which the payment may be subject to applicable insurance company regulations and capital guidance. Approximately £80 million is considered distributable from Unum Limited during 2023, subject to local solvency standards and regulatory approval. Deposits

Schedule I - Summary of Investm

Schedule I - Summary of Investments, Other Than Investments in Related Parties Schedule I - Summary of Investments, Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2022
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Summary of Investments, Other Than Investments in Related Parties	SCHEDULE I--SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES as of December 31, 2022 Unum Group and Subsidiaries Type of Investment Cost or Amortized Cost (1) Fair Value Amount shown on the balance sheet (in millions of dollars) Fixed Maturity Securities: Bonds United States Government and Government Agencies and Authorities $ 503.8 $ 498.2 $ 498.2 States, Municipalities, and Political Subdivisions 4,006.0 3,457.2 3,457.2 Foreign Governments 908.1 827.1 827.1 Public Utilities 5,170.9 4,956.9 4,956.9 Mortgage/Asset-Backed Securities 592.1 573.3 573.3 All Other Corporate Bonds 26,640.3 24,524.6 24,524.6 Redeemable Preferred Stocks 4.0 3.5 3.5 Total Fixed Maturity Securities 37,825.2 34,840.8 34,840.8 Mortgage Loans 2,444.7 2,435.4 Policy Loans 3,601.2 3,601.2 Other Long-term Investments Derivatives — 89.1 (2) Perpetual Preferred Equity Securities 23.1 25.8 (3) Private Equity Partnerships 1,032.2 1,194.3 (3) Miscellaneous Long-term Investments 130.9 130.9 Short-term Investments 1,394.8 1,394.8 Total Investments $ 46,452.1 $ 43,712.3 (1) The amortized cost for fixed maturity securities and mortgage loans represents original cost reduced by repayments, write-downs from declines in fair value, amortization of premiums, and/or accretion of discounts. The amortized cost for these investments does not include allowance for expected credit losses. (2) Derivatives are carried at fair value. (3) The difference between amortized cost and carrying value for private equity partnerships and perpetual preferred equity securities primarily results from changes in the partnership owner's equity and the security's market valuation since acquisition, respectively.

Schedule II Condensed Finacial

Schedule II Condensed Finacial Information of Registrant	12 Months Ended
	Dec. 31, 2022
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure	SCHEDULE II--CONDENSED FINANCIAL INFORMATION OF REGISTRANT Unum Group (Parent Company) BALANCE SHEETS December 31 2022 2021 (in millions of dollars) Assets Fixed Maturity Securities - at fair value (amortized cost: $748.1; $826.4) $ 657.7 $ 820.8 Other Long-term Investments 19.3 10.3 Short-term Investments 845.8 629.5 Investment in Subsidiaries 11,278.2 13,711.1 Deferred Income Tax 114.9 144.5 Other Assets 555.5 508.1 Total Assets $ 13,471.4 $ 15,824.3 Liabilities and Stockholders' Equity Liabilities Short-term Debt $ 2.0 $ — Long-term Debt 3,427.8 3,442.2 Pension and Postretirement Benefits 352.6 507.1 Other Liabilities 491.5 458.6 Total Liabilities 4,273.9 4,407.9 Stockholders' Equity Common Stock, $0.10 par Authorized: 725,000,000 shares Issued: 308,306,490 and 307,334,853 shares 30.8 30.7 Additional Paid-in Capital 2,441.0 2,408.1 Accumulated Other Comprehensive Income (Loss) (2,756.6) 354.1 Retained Earnings 12,912.1 11,853.2 Treasury Stock - at cost: 110,551,977 and 104,820,670 shares (3,429.8) (3,229.7) Total Stockholders' Equity 9,197.5 11,416.4 Total Liabilities and Stockholders' Equity $ 13,471.4 $ 15,824.3 SCHEDULE II--CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Continued) Unum Group (Parent Company) STATEMENTS OF OPERATIONS Year Ended December 31 2022 2021 2020 (in millions of dollars) Cash Dividends from Subsidiaries $ 1,306.6 $ 909.8 $ 974.6 Non-Cash Dividends from Subsidiaries 23.0 719.6 — Other Income 81.8 53.5 51.7 Total Revenue 1,411.4 1,682.9 1,026.3 Interest and Debt Expense 188.5 185.9 187.1 Cost Related to Early Retirement of Debt 4.2 67.3 — Other Expenses 35.6 39.1 51.1 Total Expenses 228.3 292.3 238.2 Income of Parent Company Before Income Tax 1,183.1 1,390.6 788.1 Income Tax Expense (Benefit) 14.7 (24.1) (15.3) Income of Parent Company 1,168.4 1,414.7 803.4 Equity in Undistributed Earnings (Loss) of Subsidiaries 145.8 (590.5) (10.4) Net Income 1,314.2 824.2 793.0 Other Comprehensive Income (Loss), Net of Tax (3,110.7) (20.1) 336.9 Comprehensive Income (Loss) $ (1,796.5) $ 804.1 $ 1,129.9 SCHEDULE II--CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Continued) Unum Group (Parent Company) STATEMENTS OF CASH FLOWS Year Ended December 31 2022 2021 2020 (in millions of dollars) Cash Provided by Operating Activities $ 1,250.2 $ 861.0 $ 964.0 Cash Flows from Investing Activities Proceeds from Sales and Maturities of Fixed Maturity Securities 192.1 245.5 138.8 Proceeds from Sales and Maturities of Other Investments 7.4 20.1 46.6 Purchase of Fixed Maturity Securities (102.7) (2.0) (384.7) Purchase of Other Investments (32.0) (0.9) (22.0) Net Sales (Purchases) of Short-term Investments (209.6) (465.0) 440.6 Cash Distributions to Subsidiaries (540.2) (300.9) (965.5) Net Purchases of Property and Equipment (94.0) (91.3) (81.6) Cash Used by Investing Activities (779.0) (594.5) (827.8) Cash Flows from Financing Activities Short-term Debt Repayment — — (400.0) Issuance of Long-term Debt 349.2 588.1 494.1 Long-term Debt Repayment (364.0) (500.0) — Cost Related to Early Retirement of Debt (3.6) (62.8) — Issuance of Common Stock 4.0 3.4 4.4 Repurchase of Common Stock (200.1) (50.0) — Dividends Paid to Stockholders (254.2) (239.4) (231.9) Other, Net 0.7 (1.6) (1.4) Cash Used by Financing Activities (468.0) (262.3) (134.8) Increase in Cash $ 3.2 $ 4.2 $ 1.4

Schedule III Supplementary Insu

Schedule III Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2022
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Supplementary Insurance Information, for Insurance Companies Disclosure	SCHEDULE III--SUPPLEMENTARY INSURANCE INFORMATION Unum Group and Subsidiaries Segment Deferred Acquisition Costs Reserves for Future Policy Contract Benefits Unearned Premiums Policy and Contract Benefits (in millions of dollars) December 31, 2022 Unum US $ 1,089.4 $ 9,129.9 $ 50.5 $ 1,245.8 Unum International 36.6 2,074.7 130.4 165.2 Colonial Life 1,126.3 2,750.2 35.2 181.5 Closed Block — 28,375.4 136.6 247.3 Total $ 2,252.3 $ 42,330.2 $ 352.7 $ 1,839.8 December 31, 2021 Unum US $ 1,096.2 $ 10,959.4 $ 41.5 $ 1,262.5 Unum International 35.4 2,765.5 131.8 171.2 Colonial Life 1,076.3 2,730.1 36.3 210.3 Closed Block — 31,552.5 137.9 263.7 Total $ 2,207.9 $ 48,007.5 $ 347.5 $ 1,907.7 SCHEDULE III--SUPPLEMENTARY INSURANCE INFORMATION (Continued) Unum Group and Subsidiaries Segment Premium Income Net Investment Income 1 Benefits and Change in Reserves for Future Benefits 2 Amortization of Deferred Acquisition Costs All Other Expenses 3 Premiums Written 4 (in millions of dollars) December 31, 2022 Unum US $ 6,258.3 $ 676.3 $ 3,941.5 $ 294.9 $ 1,768.8 $ 4,335.7 Unum International 718.8 170.1 564.8 7.6 190.4 504.1 Colonial Life 1,702.0 152.7 803.1 288.5 389.6 1,221.8 Closed Block 944.3 1,070.6 1,627.3 — 261.5 936.8 Corporate — 52.5 — — 221.6 — Total $ 9,623.4 $ 2,122.2 $ 6,936.7 $ 591.0 $ 2,831.9 December 31, 2021 Unum US $ 6,078.0 $ 721.6 $ 4,338.8 $ 319.0 $ 1,631.9 $ 4,168.9 Unum International 717.0 132.7 556.2 8.0 180.4 520.6 Colonial Life 1,690.2 172.0 910.4 259.1 364.5 1,223.3 Closed Block 995.8 1,159.0 1,793.2 — 284.0 983.0 Corporate — 27.9 — — 305.3 — Total $ 9,481.0 $ 2,213.2 $ 7,598.6 $ 586.1 $ 2,766.1 December 31, 2020 Unum US $ 6,018.9 $ 720.3 $ 4,138.7 $ 341.0 $ 1,589.0 $ 4,088.6 Unum International 652.8 104.6 500.9 7.4 173.0 456.0 Colonial Life 1,712.0 155.7 906.5 257.7 369.2 1,252.4 Closed Block 994.4 1,370.3 3,426.8 — 240.2 979.3 Corporate — 9.8 — — 247.7 — Total $ 9,378.1 $ 2,360.7 $ 8,972.9 $ 606.1 $ 2,619.1 1 Net investment income is allocated based upon segmentation. Each segment has its own specifically identified assets and receives the investment income generated by those assets. 2 Included in benefits and change in reserves for future benefits were the following: • In 2022, a reserve decrease in the Unum US segment related to reserve assumption updates in our Unum US group long-term disability and group life product lines, of $121.0 million and $34.0 million, respectively. • In 2021, a reserve decrease of $215.0 million in the Unum US segment related to reserve assumption updates in our Unum US group long-term disability product line. Also in 2021, reserve increases in the Closed Block segment related to reserve assumption updates for our long-term care, group pension, and individual disability product lines, of $2.1 million, $25.1 million, and $6.4 million, respectively. • In 2020, reserve increases in the Closed Block segment related to reserve assumption updates for our long-term care and group pension product lines of $151.5 million and $17.5 million, respectively. • In 2021 and 2020, an increase in benefits and change in reserves for future benefits of $133.1 million and $1,284.5 million, respectively, resulting from the recognition of the adjustment related to unrealized investment gains and losses previously recognized in accumulated other comprehensive income related to the Closed Block individual disability reinsurance transaction. SCHEDULE III--SUPPLEMENTARY INSURANCE INFORMATION (Continued) Unum Group and Subsidiaries 3 Includes commissions, interest and debt expense, deferral of acquisition costs, compensation expense, and other expenses. Where not directly attributable to a segment, expenses are generally allocated based on activity levels, time information, and usage statistics. Also included in all other expenses were the following: • In 2022, 2021, and 2020 the amortization of the cost of reinsurance of $63.8 million, $79.1 million, and $2.6 million respectively, in the Closed Block segment. • In 2021, an impairment loss of $12.1 million was recorded in our Corporate segment for previously capitalized internal-use software that we no longer plan to utilize. • In 2021, costs related to early retirement of debt of $67.3 million in the Corporate segment. • In 2021 and 2020, transaction costs of $6.2 million and $21.0 million, respectively, related to the Closed Block individual disability reinsurance transaction. • In 2021 and 2020, a right-of-use asset impairment of $13.9 million and $12.7 million, respectively, related to one of our operating leases for office space that we do not plan to continue using to support general operations in the Corporate segment. • In 2020, costs related to organizational design updates of $23.3 million in the Corporate segment. 4 Excludes life insurance.

Schedule IV Reinsurance

Schedule IV Reinsurance	12 Months Ended
	Dec. 31, 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Supplemental Schedule of Reinsurance Premiums for Insurance Companies	SCHEDULE IV--REINSURANCE Unum Group and Subsidiaries Gross Amount Ceded to Other Companies Assumed from Other Companies Net Amount Percentage Amount Assumed to Net (in millions of dollars) Year Ended December 31, 2022 Life Insurance in Force $ 1,057,312.2 $ 35,773.9 $ 931.9 $ 1,022,470.2 0.1 % Premium Income: Life Insurance $ 2,711.2 $ 155.1 $ 6.5 $ 2,562.6 0.3 % Accident, Health, and Other Insurance 7,189.3 200.7 72.2 7,060.8 1.0 % Total $ 9,900.5 $ 355.8 $ 78.7 $ 9,623.4 0.8 % Year Ended December 31, 2021 Life Insurance in Force $ 1,007,562.2 $ 37,794.6 $ 920.3 $ 970,687.9 0.1 % Premium Income: Life Insurance $ 2,550.7 $ 150.2 $ 7.6 $ 2,408.1 0.3 % Accident, Health, and Other Insurance 7,192.1 202.2 83.0 7,072.9 1.2 % Total $ 9,742.8 $ 352.4 $ 90.6 $ 9,481.0 1.0 % Year Ended December 31, 2020 Life Insurance in Force $ 979,755.7 $ 41,550.9 $ 896.4 $ 939,101.2 0.1 % Premium Income: Life Insurance $ 2,536.8 $ 141.9 $ 8.0 $ 2,402.9 0.3 % Accident, Health, and Other Insurance 7,085.1 196.0 86.1 6,975.2 1.2 % Total $ 9,621.9 $ 337.9 $ 94.1 $ 9,378.1 1.0 %

Schedule V Valuation and Qualif

Schedule V Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2022
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts Disclosure	SCHEDULE V--VALUATION AND QUALIFYING ACCOUNTS Unum Group and Subsidiaries Description Balance at Beginning of Year 1 Additions Charged to Costs and Expenses Additions Charged to Other Accounts 2 Deductions 3 Balance at End of Year (in millions of dollars) Year Ended December 31, 2022 Allowance for expected credit losses (deducted from accounts and premiums receivable) $ 34.2 $ 10.8 $ — $ 12.5 $ 32.5 Allowance for expected credit losses (deducted from reinsurance recoverable) $ 2.3 $ — $ — $ 0.6 $ 1.7 Year Ended December 31, 2021 Allowance for expected credit losses (deducted from accounts and premiums receivable) $ 38.8 $ 18.2 $ — $ 22.8 $ 34.2 Allowance for expected credit losses (deducted from reinsurance recoverable) $ 11.7 $ 0.7 $ — $ 10.1 $ 2.3 Year Ended December 31, 2020 Real Estate reserve (deducted from other long-term investments) $ 0.3 $ — $ — $ 0.3 $ — Allowance for expected credit losses (deducted from accounts and premiums receivable) $ 23.8 $ 34.2 $ 0.1 $ 19.3 $ 38.8 Allowance for doubtful accounts (deducted from reinsurance recoverable) $ 1.8 $ 10.1 $ — $ 0.2 $ 11.7 1 In 2020, ASC 326 "Financial Instruments - Credit Losses" was adopted resulting in a beginning balance adjustment of $13.5 million to increase the Allowance for expected credit losses (deducted from accounts and premiums receivable) and a $1.8 million beginning balance adjustment to increase the Allowance for expected credit losses (deducted from reinsurance recoverable). 2 Additions charged to other accounts are comprised of amounts related to fluctuations in the foreign currency exchange rate. 3 Deductions include amounts deemed to reduce exposure of expected losses on premium and accounts receivables and reinsurance recoverable, probable losses on Real Estate reserve, amounts deemed uncollectible, and amounts related to fluctuations in the foreign currency exchange rate. Certain items not reported above include the allowance for expected credit losses on mortgage loans, the allowance for credit losses on fixed maturity securities, and the deferred tax asset valuation allowance. See Notes 3 and 7 of the "Notes to Consolidated Financial Statements" contained herein in Item 8 for a discussion of these items.

Signficant Accounting Policies

Signficant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting policies and error corrections [Abstract]
Basis of Presentation	Basis of Presentation: The accompanying consolidated financial statements of Unum Group and its subsidiaries (the Company) have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). Such accounting principles differ from statutory accounting principles (see Note 16). Intercompany transactions have been eliminated.
Use of Estimates	Use of Estimates : The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Such estimates and assumptions could change in the future as more information becomes known, which could impact the amounts reported and disclosed herein. In accordance with standard practice, we regularly review the methodology used in the development of all key estimates. As a result of this review, in 2022, we updated our estimate of the unearned premium reserve for certain of our product lines to utilize a gross unearned premium reserve rather than a net unearned premium reserve. The effect of this change in estimate was to decrease 2022 premium income by $13.4 million and decrease commissions by $1.0 million. This resulted in a decrease to net income of $9.8 million and a decrease to both basic and diluted earnings per share by $0.05.
Fixed Maturity Securities	Fixed Maturity Securities : Fixed maturity securities include long-term bonds and redeemable preferred stocks. Our fixed maturity securities are classified as available-for-sale and reported at fair value. Changes in the fair value of available-for-sale fixed maturity securities, except for amounts related to impairment and credit losses recognized in earnings, are reported as a component of other comprehensive income. These amounts are net of income tax and valuation adjustments to deferred acquisition costs and reserves for future policy and contract benefits which would have been recorded had the related unrealized gain or loss on these securities been realized. Realized investment gains or losses are based upon specific identification of the investments sold. Interest income is recorded as part of net investment income when earned, using an effective yield method giving effect to amortization of premium and accretion of discount. Included within fixed maturity securities are mortgage-backed and asset-backed securities. We recognize investment income on these securities using a constant effective yield based on projected prepayments of the underlying loans and the estimated economic life of the securities. Actual prepayment experience is reviewed periodically, and effective yields are recalculated when differences arise between prepayments originally projected and the actual prepayments received and currently projected. The effective yield is recalculated on a retrospective basis, and the adjustment is reflected in net investment income. For fixed maturity securities on which collection of investment income is uncertain, we discontinue the accrual of investment income and recognize investment income when interest and dividends are received. Payment terms specified for fixed maturity securities may include a prepayment penalty for unscheduled payoff of the investment. Prepayment penalties are recognized as investment income when received. In determining when a decline in fair value below amortized cost of a fixed maturity security is a credit loss, we evaluate available information, both positive and negative, in reaching our conclusions. In particular, we consider the strength of the issuer's balance sheet, its debt obligations and near-term funding requirements, cash flow and liquidity, the profitability of its core businesses, the availability of marketable assets which could be sold to increase liquidity, its industry fundamentals and regulatory environment, and its access to capital markets. Although all available and applicable factors are considered in our analysis, our expectation of recovering the entire amortized cost basis of the security, whether we intend to sell the security, whether it is more likely than not that we will be required to sell the security before recovery of its amortized cost, and whether the security is current on principal and interest payments are the most critical factors in determining whether impairments represent credit losses. The significance of the decline in value is also an important factor, but we generally do not record an impairment loss based solely on this factor, since often other more relevant factors will impact our evaluation of a security. For securities with a decline in fair value below amortized cost which we intend to sell or more likely than not will be required to sell before recovery in value, the amortized cost of the investment is written down to fair value through earnings, and an impairment loss is recognized in the current period. For securities that we believe are impaired and which we do not intend to
Mortgage Loans	Mortgage Loans : Mortgage loans are generally held for investment and are carried at amortized cost less an allowance for expected credit losses. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. Prepayment penalties are recognized as investment income when received. For mortgage loans on which collection of interest income is uncertain, we discontinue the accrual of interest and recognize it in the period when an interest payment is received. We typically do not resume the accrual of interest on mortgage loans on nonaccrual status until there are significant improvements in the underlying financial condition of the borrower. We consider a loan to be delinquent if full payment is not received in accordance with the contractual terms of the loan. We evaluate each of our mortgage loans individually for impairment and assign an internal credit quality rating based on a comprehensive rating system used to evaluate the credit risk of the loan. Although all available and applicable factors are considered in our analysis, loan-to-value and debt service coverage ratios are the most critical factors in determining impairment. We estimate an allowance for credit losses that we expect to incur over the life of our mortgage loans using a probability of default method. For each loan, we estimate the probability that the loan will default before its maturity (probability of default) and the amount of the loss if the loan defaults (loss given default). These two factors result in an expected loss percentage that is applied to the amortized cost of each loan to determine the expected credit loss. As we are the original underwriter of the mortgage loans, the amortized cost generally equals the principal amount of the loan. We measure losses on defaults of our mortgage loans as the excess amortized cost of the mortgage loan over the fair value of the underlying collateral in the event that we foreclose on the loan or over the expected future cash flows of the loan if we retain the mortgage loan until payoff. We do not purchase mortgage loans with existing credit impairments. In estimating the probability of default, we consider historical experience, current market conditions, and reasonable and supportable forecasts about the future market conditions. We utilize our historical loan experience in combination with a large third-party industry database for a period of time that aligns with the average life of our loans based on the maturity dates of the loans and prepayment experience. Our model utilizes an industry database of the historical loss experience based on our actual portfolio characteristics such as loan-to-value, debt service coverage, collateral type, geography, and late payment history. In addition, because we actively manage our portfolio, we may extend the term of a loan in certain situations and will accordingly extend the maturity date in the estimate of probability of default. In estimating the loss given default, we primarily consider the type and value of collateral and secondarily the expected liquidation costs and time to recovery. The primary market factors that we consider in our forecast of future market conditions are gross domestic product, unemployment rates, interest rates, inflation, commercial real estate values, household formation, and retail sales. We also forecast certain loan specific factors such as growth in the fair value and net operating income of collateral by property type. We include our estimate of these factors over a two-year period and for the remainder of the loans’ estimated lives, adjusted for estimated prepayments. Past the two-year forecast period, we revert to the historical assumptions ratably by the end of the fifth year of the loan after which we utilize only historical assumptions. We utilize various scenarios to estimate our allowance for expected losses ranging from a base case scenario that reflects normal market conditions to a severe case scenario that reflects adverse market conditions. We will adjust our allowance each period to utilize the scenario or weighting of the scenarios that best reflects our view of current market conditions. Additions and reductions to our allowance for credit losses on mortgage loans are reported as a component of net investment gains and losses. See Note 3.
Policy Loans	Policy Loans : Policy loans
Investments	Other Long-term Investments : Other long-term investments are comprised primarily of private equity partnerships, real estate, perpetual preferred stock, common stock, and tax credit partnerships. Our investments in private equity partnerships are passive in nature and represent funds that are primarily invested in private credit, private equity, and real assets. We account for our investments in these partnerships using either the equity method or at fair value through net income depending on the level of ownership and the degree of our influence over partnership operating and financial policies. For investments in partnerships accounted for under the equity method, we report our investments at our share of the partnership's net asset value (NAV) and record our portion of partnership earnings as a component of net investment income. For investments in partnerships accounted for at fair value through net income, we also report our investments at our share of the partnership's NAV as a practical expedient for fair value with increases or decreases recorded as a component of net investment income. Distributions received from the funds arise from income generated by the underlying investments as well as the liquidation of the underlying investments and there is generally not a public market for these investments. Investment real estate is primarily comprised of property held for the production of income and property held for sale. Property held for the production of income is carried at cost less accumulated depreciation and any write-downs to fair value for impairment losses. Depreciation is recorded on a straight-line basis over the estimated useful life of the asset. A review for impairment is made whenever events or circumstances indicate that the carrying value may not be recoverable. An impairment loss is recognized when the carrying value of the property exceeds the expected undiscounted cash flows generated from the property, at which point the carrying value is written down to an estimated fair value. Real estate held for sale is carried at the lower of depreciated cost or fair value less estimated selling costs and is not further depreciated once classified as such. Our perpetual preferred stocks are valued at fair value, based on quoted market prices, where available. For preferred stocks not actively traded, fair values are estimated using values obtained from independent pricing services. Our investments in common stock are valued at fair value. Our shares of Federal Home Loan Bank (FHLB) common stock are carried at cost, which approximates fair value. Tax credit partnerships in which we have invested were formed for the purpose of investing in the construction and rehabilitation of low-income housing. Because the partnerships are structured such that there is no return of principal, the primary sources of investment return from our tax credit partnerships are tax credits and tax benefits derived from passive losses on the investments, both of which may exhibit variability over the life of the investment. These partnerships are accounted for using either the proportional or the effective yield method, depending primarily on whether the tax credits are guaranteed through a letter of credit, a tax indemnity agreement, or another similar arrangement. Tax credits received from these partnerships are reported in our consolidated statements of income as either a reduction of premium tax or a reduction of income tax. The amortization of the principal amount invested in these partnerships is reported as a component of either premium tax or income tax. See Notes 2 and 3 for further discussion of our other long-term investments. Short-term Investments :
Cash and Bank Deposits	Cash and Bank Deposits: Cash and bank deposits include cash on hand and non-interest bearing cash and deposit accounts.
Derivative Financial Instruments	Derivative Financial Instruments : Derivative financial instruments (including certain derivative instruments embedded in other contracts) are recognized as either other long-term investments or other liabilities in our consolidated balance sheets and are reported at fair value. The accounting for a derivative depends on whether it has been designated and qualifies as part of a hedging relationship, and further, on the type of hedging relationship. To qualify for hedge accounting, at the inception of the hedging transaction, we formally document the risk management objective and strategy for undertaking the hedging transaction, as well as the designation of the hedge as either a fair value hedge or a cash flow hedge. Included in this documentation is how the hedging instrument is expected to hedge the designated risk(s) related to specific assets or liabilities on the balance sheet or to specific forecasted transactions as well as a description of the method that will be used to retrospectively and prospectively assess the hedging instrument's effectiveness. A derivative designated as a hedging instrument must be assessed as being highly effective in offsetting the designated risk(s) of the hedged item. Hedge effectiveness is formally assessed at inception and periodically throughout the life of the designated hedging relationship, using qualitative and quantitative methods. Qualitative methods include comparison of critical terms of the derivative to the hedged item. Quantitative methods include regression or other statistical analysis of changes in fair value or cash flows associated with the hedge relationship. Changes in the fair value of a derivative designated as a fair value hedge and changes in the fair value of the hedged item attributable to the risk being hedged are recognized in earnings as a component of net investment gain or loss during the period of change in fair value. For gains or losses on the derivative instrument that are excluded from the assessment of hedge effectiveness, those gains and losses are recognized in other comprehensive income or loss and amortized into earnings in the same income statement line as the related hedged item. The gain or loss on the termination of a fair value hedge is recognized in earnings as a component of net investment gain or loss during the period in which the termination occurs. When interest rate swaps are used in hedge accounting relationships, periodic settlements are recorded in the same income statement line as the related settlements of the hedged items. Changes in the fair value of a derivative designated as a cash flow hedge are reported in other comprehensive income and reclassified into earnings and reported on the same income statement line item as the hedged item and in the same period or periods during which the hedged item affects earnings. The gain or loss on the termination of an effective cash flow hedge is reported in other comprehensive income and reclassified into earnings and reported on the same income statement line item as the hedged item and in the same period or periods during which the hedged item affects earnings. Gains or losses on the termination of ineffective fair value or cash flow hedges are reported in earnings as a component of net investment gain or loss. In the event a hedged item is disposed of or the anticipated transaction being hedged is no longer likely to occur, we will terminate the related derivative and recognize the gain or loss on termination in current earnings as a component of net investment gain or loss. In the event a hedged item is disposed of subsequent to the termination of the hedging transaction, we reclassify any remaining gain or loss on the hedge out of accumulated other comprehensive income into earnings as a component of the same income statement line item wherein we report the gain or loss on disposition of the hedged item. For a derivative not designated as a hedging instrument, changes in the fair value of the derivative, together with the payment of periodic fees, if applicable, are recognized in the same income statement line item as the hedged item during the period of change in fair value. Cash flow activity from the settlement of derivative contracts is reported in the consolidated statements of cash flows as a component of proceeds from sales and maturities of other investments.
Fair Value Measurement	Fair Value Measurement : Certain assets and liabilities are reported at fair value in our consolidated balance sheets and in our notes to our consolidated financial statements. We define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Therefore, fair value represents an exit price, not an entry price. The exit price objective applies regardless of our intent and/or ability to sell the asset or transfer the liability at the measurement date. Assets or liabilities with readily available actively quoted prices or for which fair value can be measured from actively quoted prices in active markets generally have more pricing observability and less judgment utilized in measuring fair value. When actively quoted prices are not available, fair values are based on quoted prices in markets that are not active, quoted prices for similar but not identical assets or liabilities, or other observable inputs. If observable inputs are not available, unobservable inputs and/or adjustments to observable inputs requiring management judgment are used to determine fair value. We categorize our assets and liabilities measured at estimated fair value into a three-level hierarchy, based on the significance of the inputs. The fair value hierarchy gives the highest priority to inputs which are
Allowance for Credit Losses on Premiums Receivable	Allowance for Credit Losses on Premiums Receivable : We establish an allowance for credit losses on premiums receivable, which is deducted from the gross amount of our receivable balance, to present the net amount we expect to collect on this asset. The allowance is forward-looking in nature and is calculated based on considerations regarding both historical events and future expectations. Periodic changes in the allowance are recorded through earnings. The allowance on our premiums receivable is primarily determined using an aging analysis as well as historical lapse and delinquency rates by line of business, adjusted for key factors that may impact our future expectation of premium receipts such as changes in customer demographics, business practices, economic conditions, and product offerings. We write off premiums receivable amounts when determined to be uncollectible, which is based on various factors, including the aging of premiums receivable past the due date and specific communication with customers. At December 31, 2022 and 2021, the allowance for expected credit losses on premium receivables was $32.5 million and $34.2 million, respectively, on gross premium receivables of $557.6 million and $530.7 million, respectively. The allowance decreased $1.7 million during the year ended December 31, 2022, and was driven primarily by improvements in the age of premiums receivable. The allowance decreased $4.6 million during the year ended December 31, 2021, driven primarily by improvements in the age of premiums receivable and improvements in unemployment levels.
Deferred Acquisition Costs	Deferred Acquisition Costs : Incremental direct costs associated with the successful acquisition of new or renewal insurance contracts have been deferred. Such costs include commissions, other agency compensation, certain selection and policy issue expenses, and certain field expenses. Acquisition costs that do not vary with the production of new business, such as commissions on group products which are generally level throughout the life of the policy, are excluded from deferral. Deferred acquisition costs are subject to recoverability testing at the time of policy issue and loss recognition testing in subsequent years. Deferred acquisition costs related to non-interest sensitive policies are amortized in proportion to the premium income we expect to receive over the lives of the policies. Deferred acquisition costs related to interest sensitive policies are amortized over the lives of the policies in relation to the present value of estimated gross profits from surrender charges, mortality margins, investment returns, and expense margins. Deviations from projections result in a change to the rate of amortization in the period during which such events occur. Generally, the amortization periods for these policies approximate the estimated lives of the policies. For certain products, policyholders can elect to modify product benefits, features, rights, or coverages by exchanging a contract for a new contract or by amendment, endorsement, or rider to a contract, or by the election of a feature or coverage within a contract. These transactions are known as internal replacement transactions. Internal replacement transactions wherein the modification does not substantially change the policy are accounted for as continuations of the replaced contracts. Unamortized deferred acquisition costs from the original policy continue to be amortized over the expected life of the new policy, and the costs of replacing the policy are accounted for as policy maintenance costs and expensed as incurred. Internal replacement transactions, principally on group contracts, that result in a policy that is substantially changed are accounted for as an extinguishment of the original policy and the issuance of a new policy. Unamortized deferred acquisition costs on the original policy that was replaced are immediately expensed, and the costs of acquiring the new policy are capitalized and amortized in accordance with our accounting policies for deferred acquisition costs. Loss recognition and recoverability testing is performed on an annual basis, or more frequently if appropriate, using best estimate assumptions as to future experience as of the date of the test. Insurance contracts are grouped for each major product line within a segment when we perform the loss recognition and recoverability tests. If loss recognition or recoverability testing indicates that deferred acquisition costs are not recoverable, the deficiency is charged to expense.
Goodwill	Goodwill : Goodwill is the excess of the amount paid to acquire a business over the fair value of the net assets acquired. We review the carrying amount of goodwill for impairment on an annual basis, or more frequently if events or changes in circumstances indicate that the carrying amount might not be recoverable. Goodwill impairment testing compares the fair value of a reporting unit with its carrying amount, including goodwill. If the fair value of the reporting unit to which the goodwill relates is less than the carrying amount of the reporting unit, an impairment charge is recognized for the amount by which the
Property and Equipment	Property and Equipment: Property and equipment is reported at cost less accumulated depreciation, which is calculated on the straight-line method over the estimated useful life. The accumulated depreciation for property and equipment was $1,328.7 million and $1,259.6 million as of December 31, 2022 and 2021, respectively.
Value of Business Acquired	Value of Business Acquired : Value of business acquired represents the present value of future profits recorded in connection with the acquisition of a block of insurance policies. The asset is amortized based upon expected future premium income for non-interest sensitive insurance policies and estimated future gross profits from surrender charges, mortality margins, investment returns, and expense margins for interest sensitive insurance policies. The value of business acquired, which is included in other assets in our consolidated balance sheets, was $62.9 million and $73.1 million at December 31, 2022 and 2021, respectively. The accumulated amortization for value of business acquired was $150.3 million and $157.7 million as of December 31, 2022 and 2021, respectively. The amortization of value of business acquired, which is included in other expenses in the consolidated statements of income, was $4.9 million, $5.7 million, and $6.1 million for the years ended December 31, 2022, 2021, and 2020, respectively. We periodically review the carrying amount of value of business acquired using the same methods used to evaluate deferred acquisition costs.
Policy and Contract Benefits	Policy and Contract Benefits : Policy and contract benefits represent amounts paid and expected to be paid based on reported losses and estimates of incurred but not reported losses for non-interest sensitive life and accident and health products. For interest sensitive products, benefits are the amounts paid and expected to be paid on insured claims in excess of the policyholders' policy fund balances.
Reserves for Policy and Contract Benefits	Reserves for Future Policy and Contract Benefits : Policy reserves represent future policy and contract benefits for claims not yet incurred. Policy reserves for non-interest sensitive life and accident and health products are determined using the net level premium method. The reserves are calculated based upon assumptions as to interest, persistency, morbidity, and mortality that were appropriate at the date of issue. Discount rate assumptions are based on actual and expected net investment returns. Persistency assumptions are based on our actual historical experience adjusted for future expectations. Claim incidence and claim resolution rate assumptions related to morbidity and mortality are based on actual experience or industry standards adjusted as appropriate to reflect our actual experience and future expectations. The assumptions vary by plan, year of issue, and policy duration and include a provision for adverse deviation. Policy reserves for group single premium annuities are developed on a net single premium method. The reserves are calculated based on assumptions as to interest, mortality, and retirement that were appropriate at the date of issue. Mortality assumptions are based upon industry standards adjusted as appropriate to reflect our actual experience and future expectations. The assumptions vary by year of issue. Policy reserves for interest sensitive products are principally policyholder account values resulting from customer deposits and interest credited less cost of insurance, policy administration expenses, surrender charges, and customer withdrawals. Policy reserves require ongoing loss recognition testing. We perform loss recognition tests on our policy reserves annually, or more frequently if appropriate, using best estimate assumptions as of the date of the test, without a provision for adverse deviation. We group the policy reserves for each major product line within a segment when we perform the loss recognition tests. If the policy reserves determined using these best estimate assumptions are higher than our existing policy reserves net of any deferred acquisition cost balance, the existing policy reserves are increased or deferred acquisition costs are reduced to immediately recognize the deficiency. This becomes the new basis for policy reserves going forward, subject to future loss recognition testing. Claim reserves represent future policy and contract benefits for claims that have been incurred or are estimated to have been incurred but not yet reported to us. Our claim reserves relate primarily to disability and long-term care policies and are calculated based on assumptions as to interest and claim resolution rates that are currently appropriate. Claim resolution rate assumptions are based on our actual experience. The interest rate assumptions used for discounting claim reserves are based on
Policyholders' Funds	Other Policyholders' Funds : Other policyholders' funds represent customer deposits plus interest credited at contract rates. We control interest rate risk by investing in quality assets which have an aggregate duration that closely matches the expected duration of life liabilities.
Income Tax	Income Tax: Deferred taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial statement purposes and the amounts used for income tax purposes. Deferred taxes have been measured using enacted statutory income tax rates and laws that are currently in effect. We record adjustments to our deferred taxes resulting from tax rate changes through income as of the date of enactment. We record deferred tax assets for tax positions taken in the U.S. and other tax jurisdictions based on our assessment of whether a position is more likely than not to be sustained upon examination based solely on its technical merits.  A valuation allowance is established for deferred tax assets when it is more likely than not that an amount will not be realized. We record tax expense related to Global Intangible Low-Taxed Income in the period in which it is incurred. We follow an aggregate portfolio approach to release disproportionate tax effects from accumulated other comprehensive income upon disposal of an entire business segment's portfolio. See Note 7.
Short-term and Long-term Debt	Short-term and Long-term Debt : Debt is generally carried at the unpaid principal balance, net of unamortized discount or premium and deferred debt issuance costs. Short-term debt consists of debt due within the next twelve months, including that portion of debt otherwise classified as long-term. The amortization of the original issue discount or premium as well as deferred debt issuance costs are recognized as a component of interest expense over the period the debt is expected to be outstanding. The carrying amount of long-term debt that is part of a fair value hedge program includes an adjustment to reflect the effect of the change in fair value attributable to the risk being hedged. Net interest settlements for fair value hedges on our long-term debt are recognized as a component of interest expense. See Note 8.
Right-of-Use Asset (ROU) and Lease Liability	Right-of-Use Asset (ROU) and Lease Liability : ROU assets represent our right to use an underlying asset for a specified lease term and are included in other assets in our consolidated balance sheet. Lease liabilities represent the present value of lease payments that we are obligated to pay arising from a lease and are included in other liabilities in our consolidated balance sheet. We determine if an arrangement is a lease at inception through a formal process that evaluates our right to control the use of an identified asset for a period of time in exchange for consideration. We account for the lease and non-lease components of our building leases separately and have elected to use the available practical expedient to account for the lease and non-lease components of our equipment leases as a single component. All of our leases are classified as operating. For each operating lease, we calculate a lease liability at commencement date based on the present value of lease payments over the lease term and a corresponding ROU asset, adjusted for lease incentives. We do not recognize right-of-use assets and lease liabilities that arise from short-term leases for any class of underlying asset. We consider the likelihood of renewal in determining the lease terms for the calculation of the ROU asset and lease liability. As most of our leases do not provide an implicit rate of interest, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. We use the implicit rate of interest when readily determinable. Operating lease cost is calculated on a straight-line basis over the lease term and is included in other expenses in our consolidated statements of income. We amortize the ROU asset over the lease term on a pattern determined by the difference between the straight-line lease liability expense and the accretion of the imputed interest calculated on the lease liability. See Note 15.
Separation of Lease and Nonlease Components	We account for the lease and non-lease components of our building leases separately and have elected to use the available practical expedient to account for the lease and non-lease components of our equipment leases as a single component.
Short-term Leases	We do not recognize right-of-use assets and lease liabilities that arise from short-term leases for any class of underlying asset.
Treasury Stock and Retirement of Common Stock	Treasury Stock and Retirement of Common Stock : Treasury stock is reflected as a reduction of stockholders' equity at cost. When shares are retired, the par value is removed from common stock, and the excess of the repurchase price over par is allocated between additional paid-in capital and retained earnings. See Note 10.
Revenue Recognition	Revenue Recognition: Our non-interest sensitive life and accident and health products are long-duration contracts, and premium income is recognized as revenue when due from policyholders. If the contracts are experience rated, the estimated ultimate premium is recognized as revenue over the period of the contract. The estimated ultimate premium, which is revised to reflect current experience, is based on estimated claim costs, expenses, and profit margins. For interest sensitive products, the amounts collected from policyholders are considered deposits, and only the deductions during the period for cost of insurance, policy administration, and surrenders are included in revenue. Policyholders' funds represent funds deposited by contract holders and are not included in revenue.
Revenue from Service Fees	Fees from our leave management services and administrative-services only (ASO) business are reported as other income when services are rendered.
Reinsurance	Reinsurance : We routinely enter into reinsurance agreements with other insurance companies to spread risk and thereby limit losses from large exposures. For each of our reinsurance agreements, we determine if the agreement provides indemnification against loss or liability relating to insurance risk in accordance with applicable accounting standards. If we determine that a reinsurance agreement does not expose the reinsurer to a reasonable possibility of a significant loss from insurance risk, we record the agreement using the deposit method of accounting. Reinsurance activity is accounted for on a basis consistent with the terms of the reinsurance contracts and the accounting used for the original policies issued. Premium income and benefits and change in reserves for future benefits are presented in our consolidated statements of income net of reinsurance ceded. Ceded liabilities for policy and contract benefits, future policy and contract benefits, and unearned premiums are reported on a gross basis in our consolidated balance sheets, as are ceded policy loans. Our reinsurance recoverable includes the balances due from reinsurers under the terms of the reinsurance agreements for these ceded balances as well as settlement amounts currently due. Where applicable, gains or costs recognized on reinsurance transactions are generally deferred and amortized into earnings based upon expected future premium income for non-interest sensitive insurance policies and estimated future gross profits for interest sensitive insurance policies. Gains or costs recognized on reinsurance transactions for non-interest sensitive products for which we no longer receive premiums are generally deferred and amortized into earnings based upon expected claim reserve patterns. The cost of reinsurance included in other assets in our consolidated balance sheets at December 31, 2022 and 2021 was $713.3 million and $777.1 million. The deferred gain on reinsurance included in other liabilities in our consolidated balance sheets at December 31, 2022 and 2021 was $3.1 million and $3.7 million, respectively. Under ceded reinsurance agreements wherein we are not relieved of our legal liability to our policyholders, if the assuming reinsurer is unable to meet its obligations, we remain contingently liable. We evaluate the financial condition of reinsurers and monitor concentration of credit risk to minimize this exposure. We may also require assets in trust, letters of credit, or other acceptable collateral to support our reinsurance recoverable balances. We estimate an allowance for expected credit losses for our reinsurance recoverable balance using a probability of default approach which incorporates key inputs and assumptions regarding market factors, counterparty credit ratings, and collateral received. When calculating our allowance, we apply these market factors to the net amount of our credit exposure, which considers collateral arrangements such as letters of credit and trust accounts. We evaluate the factors used to determine our allowance on a quarterly basis to consider material changes in our assumptions and make adjustments accordingly. At December 31, 2022 and 2021, the allowance for expected credit losses on reinsurance recoverables was $1.7 million and $2.3 million, respectively. The allowance decreased $0.6 million and $9.4 million during the years ended December 31, 2022, and 2021, respectively. The decreases are primarily due to changes in the composition of the related receivable. See Note 12.
Premium Tax Expense	Premium Tax Expense : Premium tax expense is included in other expenses in the consolidated statements of income. For the years ended December 31, 2022, 2021, and 2020, premium tax expense was $169.3 million, $166.0 million, and $175.5 million, respectively.
Stock-Based Compensation	Stock-Based Compensation : The cost of stock-based compensation is generally measured based on the grant-date fair value of the award. The Black-Scholes options valuation model is used for estimating the fair value of stock options, and the Monte-Carlo valuation model is used for estimating the fair value of performance units. Restricted stock units and stock success units are valued based on the fair value of common stock at the grant date. Stock-based awards are expensed over the requisite service
Earnings Per Share	Earnings Per Share : We compute basic earnings per share by dividing net income by the weighted average number of common shares outstanding for the period. Earnings per share assuming dilution is computed by dividing net income by the weighted average number of shares outstanding for the period plus the shares representing the dilutive effect of stock-based awards. In computing earnings per share assuming dilution, only potential common shares resulting from stock-based awards that are dilutive (those that reduce earnings per share) are included. We use the treasury stock method to account for the effect of outstanding stock options and nonvested stock awards on the computation of earnings per share assuming dilution. See Note 10.
Translation of Foreign Curency	Translation of Foreign Currency : Revenues and expenses of our foreign operations are translated at average exchange rates. Assets and liabilities are translated at the rate of exchange on the balance sheet dates. The translation gain or loss is generally reported in accumulated other comprehensive income, net of income tax. We do not provide for deferred taxes to the extent unremitted foreign earnings are deemed permanently invested.
Accounting for Participating Individual Life Insurance	Accounting for Participating Individual Life Insurance : Participating policies issued by one of our subsidiaries prior to its 1986 conversion from a mutual to a stock life insurance company will remain participating as long as the policies remain in-force. A Participation Fund Account (PFA) was established for the benefit of all such individual participating life and annuity policies and contracts. The assets of the PFA provide for the benefit, dividend, and certain expense obligations of the participating individual life insurance policies and annuity contracts. The assets of the PFA were $250.2 million and $297.7 million at December 31, 2022 and 2021, respectively.
Accounting Updates Outstanding	Accounting Updates Outstanding: ASU 2020-04 , Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting and related amendments The amendments in this update provide optional guidance, for a limited period of time, to ease the potential burden in accounting for and recognizing the effects of reference rate reform on financial reporting. The guidance allows for various practical expedients and exceptions when applying GAAP to contracts, hedging relationships, and other transactions affected either by discontinued rates as a direct result of reference rate reform or a market-wide change in interest rates used for discounting, margining or contract price alignment, if certain criteria are met. Specifically, the guidance provides certain practical expedients for contract modifications, fair value hedges, and cash flow hedges, and also provides certain exceptions related to changes in the critical terms of a hedging relationship. The guidance also allows for a one-time election to sell or transfer debt securities that were both classified as held-to-maturity prior to January 1, 2020 and reference a rate affected by the reform. The adoption of this update is permitted as of the beginning of the interim period that includes March 12, 2020 (the issuance date of the update), or any date thereafter, through December 31, 2024, at which point the guidance will sunset. We do not anticipate needing to adopt this guidance, but we will continue to monitor our contracts and hedging relationships throughout the adoption period. ASU 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts and related amendments This update significantly amends the accounting and disclosure requirements for long-duration insurance contracts. These changes include a requirement to review, and if necessary, update cash flow assumptions used to measure the liability for future policy benefits for traditional and limited-payment contracts at least annually, with changes recognized in earnings. In addition, an entity will be required to update the discount rate assumption at each reporting date using a yield that is reflective of an upper-medium grade fixed-income instrument, with changes recognized in other comprehensive income (loss) (OCI). These changes result in the elimination of the provision for risk of adverse deviation and premium deficiency (or loss recognition) testing. The update also requires that an entity measure all market risk benefits associated with deposit contracts at fair value, with changes recognized in earnings except for the portion attributable to a change in the instrument-specific credit risk, which is to be recognized in OCI. This update also simplifies the amortization of deferred acquisition costs by requiring amortization on a constant level basis over the expected term of the related contracts. Deferred acquisition costs are required to be written off for unexpected contract terminations but are no longer subject to an impairment test. Significant additional disclosures will also be required, which include disaggregated rollforwards of certain liability balances and the disclosure of qualitative and quantitative information about expected cash flows, estimates, and assumptions. The application of this guidance will vary based upon the specific requirements of the update but will generally result in either a modified retrospective or full retrospective approach with changes applied as of the beginning of the earliest period presented. Early adoption is permitted. The update is effective for periods beginning January 1, 2023. We will adopt this update effective January 1, 2023 using the modified retrospective approach with changes applied as of the beginning of the earliest period presented or January 1, 2021, also referred to as the transition date. We are continuing to evaluate the effects of implementing this update. The most significant impact at the transition date will be the requirement to update the discount rate assumption to reflect an upper-medium grade fixed-income instrument, which will be generally equivalent to a single-A interest rate matched to the duration of our insurance liabilities and will result in a decrease to accumulated other comprehensive income (loss) (AOCI) within our total stockholders’ equity balance. After the transition date, we will be required to update the discount rate each subsequent reporting period with changes recorded in OCI and expect that this could have a material impact on OCI. Our modified retrospective adoption of this update during the first quarter of 2023 will result in a decrease to AOCI as of the transition date, January 1, 2021, of approximately $6.7 billion. We expect a decrease to AOCI at December 31, 2021 in a range from approximately $5.4 billion to $5.6 billion. We expect a decrease to AOCI at December 31, 2022 in a range from approximately $0.6 billion to $0.8 billion. The decrease in AOCI in our recast of 2021 and 2022 is driven primarily by the difference between the discount rate applied under current GAAP, which is based on an expected investment yield from our current investment strategy, and the single-A discount rate that will be required as a part of the update. The most significant impact relates to our longest duration products. Our investment strategy reflects the illiquid nature of the majority of our liability cash flows and, as a result, the yields in our investment portfolios supporting the cash outflows required for these products are generally higher than a single-A yield. In addition, the discount rates currently applied to reserves for our longest duration products, such as long-term care, include an assumption for long-term yields rising to more historical levels. Our modified retrospective adoption is expected to result in an increase to net income during 2021 and 2022. We expect the increase in 2021 net income to be between approximately $145 million and $175 million, or between $0.70 and $0.85 per diluted per common share. We expect the increase in 2022 net income to be between approximately $80 million and $110 million, or $0.40 and $0.55 per diluted common share. The net favorable impact of the recast of our net income for 2021 and 2022 shown above is due primarily to the following changes: • Updating the lifetime cohort net premium ratios (lifetime loss ratio) for actual experience each reporting period will generally cause earnings patterns to be more consistent from period to period, with variances in experience reflected in earnings over the cohort lifetime. This will result in an unfavorable impact to income for 2021 and 2022. • Alignment of amortization of deferred acquisition costs to a constant level basis and modification of amortization periods to reflect the expected term of the related contracts could result in either higher or lower income for the affected product lines. This will result in a net favorable impact to income for 2021 and 2022. • Accelerated recognition of the provision for adverse deviation or other differences from current best estimate values for policies issued prior to the transition date and due to not establishing the provision for policies issued on or after the transition date will generally result in higher income most notably in the initial years after the transition date. This will result in a favorable impact to income for 2021 and 2022. • Establishing reserves for claims incurred on or after the transition date at interest rates prescribed by the update could result in either higher or lower income for the affected product lines depending on the policy issue date and the interest rate environment at that time. This will result in an unfavorable impact to income for 2021 and a favorable impact to income for 2022. • Updating cash flow assumptions could result in either higher or lower income. This will result in a favorable impact to income for 2021 and 2022. • Applying non-contemporaneous reinsurance accounting to the second phase of our Closed Block individual disability reinsurance transaction which was completed in the first quarter of 2021. The primary impacts of this change are: ◦ Reversing the increase in benefits and change in reserves for future benefits resulting from the realization of previously unrealized investment gains and losses previously recorded in AOCI that will be removed as of the transition date which will have a favorable impact on income for 2021. ◦ Remeasuring the ceded reserves as a separate cohort of reserves at interest rates prescribed by the update and the resulting change to the cost of reinsurance. The differential in the discount rate applied to the direct and ceded cohorts of business will result in an unfavorable impact to income for 2021 and 2022 partially offset by a decrease in the amortization of the cost of reinsurance as a result of a lower cost of reinsurance. We do not have products with market risk benefits.

Significant Accounting Polici_2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting policies and error corrections [Abstract]
New Accounting Pronouncements and Changes in Accounting Principles	Accounting Updates Adopted in 2022: Standard Description Date of Adoption Effect on Financial Statements ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity The amendments in this update simplified the accounting for convertible instruments by removing certain separation models in the guidance related to convertible instruments and expanded related disclosure requirements. The amendments also revised the requirements for a contract or embedded derivative that is potentially settled in an entity's own stock to be classified as equity and also amended certain guidance related to the computations of earnings per share for convertible instruments and contracts in an entity's own stock. This guidance was applied in the period of adoption. January 1, 2022 The adoption of this update did not have an effect on our financial position or results of operations, and did not expand our disclosures. Accounting Updates Adopted in 2021: Standard Description Date of Adoption Effect on Financial Statements ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes The amendments in this update simplified the accounting for income taxes by removing certain exceptions in the guidance related to the following: 1. losses in continuing operations when there is income in other items, 2. foreign subsidiaries becoming equity method investments and vice versa, and 3. year-to-date interim period losses exceeding anticipated loss for the year. The amendments also simplified the accounting for income taxes related to the following: 1. franchise taxes partially based on income, 2. step up in the tax basis of goodwill, 3. allocation of tax expense to entities not subject to tax, 4. enacted changes in tax law or rates in interim periods, and 5. employee stock ownership programs and investments in qualified affordable housing projects accounted for using the equity method. January 1, 2021 The adoption of this update did not have a material effect on our financial position or results of operations. Accounting Updates Adopted in 2020: Standard Description Date of Adoption Effect on Financial Statements ASU 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment This update eliminated the requirement to calculate the implied fair value of goodwill (the second step in the former two-step test) to measure a goodwill impairment charge. Instead, entities should perform the goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the excess of the carrying amount over the fair value, with the loss not to exceed the total amount of goodwill allocated to that reporting unit. This guidance was applied in the period of adoption. January 1, 2020 The adoption of this update did not have an effect on our financial position or results of operations. ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement This update amended the fair value measurement guidance by removing or clarifying certain existing disclosure requirements, while also adding new disclosure requirements. Specifically, this update removed certain disclosures related to Level 1 and Level 2 transfers and removed the discussion regarding valuation processes of Level 3 fair value measurements. The update modified guidance related to investments in certain entities that calculate net asset value to explicitly require disclosure regarding timing of liquidation of the investee's assets and timing of redemption restrictions. The update added disclosures around the changes in unrealized gains and losses in other comprehensive income for recurring Level 3 investments held at the end of the reporting period and adds disclosures regarding certain unobservable inputs on Level 3 fair value measurements. The guidance was applied both retrospectively and prospectively, depending on the specific requirement of the update. December 31, 2018 for the removal and modification of certain disclosures and January 1, 2020 for the addition of certain disclosures. The adoption of this update modified our disclosures but did not have an impact on our financial position or results of operations. Standard Description Date of Adoption Effect on Financial Statements ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans This update amends the defined benefit pension and other postretirement benefit guidance by removing or clarifying certain existing disclosure requirements, while also adding new disclosure requirements. Specifically, this update removes the requirement to disclose the effects of a one-percentage point change in the assumed healthcare cost trend and the requirement to disclose amounts in accumulated other comprehensive income expected to be recognized as part of net periodic benefit cost of the next year. This update adds a requirement to describe the reasons for significant gains and losses related to changes in the benefit obligation for the period. The update also clarifies that the projected benefit obligation (PBO) and accumulated benefit obligation (ABO) and fair value of plan assets are to be disclosed for plans with PBOs or ABOs in excess of plan assets. The guidance was applied retrospectively. December 31, 2020 The adoption of this update modified our disclosures but did not have an impact on our financial position or results of operations. ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses This update amended the guidance on the impairment of financial instruments. The update added an impairment model known as the current expected credit loss model that is based on expected losses rather than incurred losses and will generally result in earlier recognition of allowances for losses. The current expected credit loss model applies to financial instruments such as mortgage loans, fixed maturity securities classified as held-to-maturity, and certain receivables. The update also modified the other-than-temporary impairment model used for available-for-sale fixed maturity securities such that credit losses are recognized as an allowance rather than as a reduction in the amortized cost of the security. The reversal of previously recognized credit losses on available-for-sale fixed maturity securities is allowed under specified circumstances. Additional disclosures are also required, including information used to develop the allowance for losses. The guidance was applied using a modified retrospective approach through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. For available-for-sale fixed maturity securities, the update was applied prospectively. Other-than-temporary impairment losses recognized on available-for-sale fixed maturity securities prior to adoption of the update cannot be reversed. This guidance was applied in the period of adoption. January 1, 2020 The adoption of this update resulted in a cumulative-effect reduction to retained earnings of $18.9 million with a corresponding decrease to mortgage loans of $8.3 million, a decrease to accounts and premiums receivable of $13.5 million and a decrease to deferred income tax of $5.0 million. There were also immaterial impacts to reinsurance recoverable and other liabilities. Accounting Updates Outstanding: ASU 2020-04 , Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting and related amendments The amendments in this update provide optional guidance, for a limited period of time, to ease the potential burden in accounting for and recognizing the effects of reference rate reform on financial reporting. The guidance allows for various practical expedients and exceptions when applying GAAP to contracts, hedging relationships, and other transactions affected either by discontinued rates as a direct result of reference rate reform or a market-wide change in interest rates used for discounting, margining or contract price alignment, if certain criteria are met. Specifically, the guidance provides certain practical expedients for contract modifications, fair value hedges, and cash flow hedges, and also provides certain exceptions related to changes in the critical terms of a hedging relationship. The guidance also allows for a one-time election to sell or transfer debt securities that were both classified as held-to-maturity prior to January 1, 2020 and reference a rate affected by the reform. The adoption of this update is permitted as of the beginning of the interim period that includes March 12, 2020 (the issuance date of the update), or any date thereafter, through December 31, 2024, at which point the guidance will sunset. We do not anticipate needing to adopt this guidance, but we will continue to monitor our contracts and hedging relationships throughout the adoption period. ASU 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts and related amendments This update significantly amends the accounting and disclosure requirements for long-duration insurance contracts. These changes include a requirement to review, and if necessary, update cash flow assumptions used to measure the liability for future policy benefits for traditional and limited-payment contracts at least annually, with changes recognized in earnings. In addition, an entity will be required to update the discount rate assumption at each reporting date using a yield that is reflective of an upper-medium grade fixed-income instrument, with changes recognized in other comprehensive income (loss) (OCI). These changes result in the elimination of the provision for risk of adverse deviation and premium deficiency (or loss recognition) testing. The update also requires that an entity measure all market risk benefits associated with deposit contracts at fair value, with changes recognized in earnings except for the portion attributable to a change in the instrument-specific credit risk, which is to be recognized in OCI. This update also simplifies the amortization of deferred acquisition costs by requiring amortization on a constant level basis over the expected term of the related contracts. Deferred acquisition costs are required to be written off for unexpected contract terminations but are no longer subject to an impairment test. Significant additional disclosures will also be required, which include disaggregated rollforwards of certain liability balances and the disclosure of qualitative and quantitative information about expected cash flows, estimates, and assumptions. The application of this guidance will vary based upon the specific requirements of the update but will generally result in either a modified retrospective or full retrospective approach with changes applied as of the beginning of the earliest period presented. Early adoption is permitted. The update is effective for periods beginning January 1, 2023. We will adopt this update effective January 1, 2023 using the modified retrospective approach with changes applied as of the beginning of the earliest period presented or January 1, 2021, also referred to as the transition date. We are continuing to evaluate the effects of implementing this update. The most significant impact at the transition date will be the requirement to update the discount rate assumption to reflect an upper-medium grade fixed-income instrument, which will be generally equivalent to a single-A interest rate matched to the duration of our insurance liabilities and will result in a decrease to accumulated other comprehensive income (loss) (AOCI) within our total stockholders’ equity balance. After the transition date, we will be required to update the discount rate each subsequent reporting period with changes recorded in OCI and expect that this could have a material impact on OCI. Our modified retrospective adoption of this update during the first quarter of 2023 will result in a decrease to AOCI as of the transition date, January 1, 2021, of approximately $6.7 billion. We expect a decrease to AOCI at December 31, 2021 in a range from approximately $5.4 billion to $5.6 billion. We expect a decrease to AOCI at December 31, 2022 in a range from approximately $0.6 billion to $0.8 billion. The decrease in AOCI in our recast of 2021 and 2022 is driven primarily by the difference between the discount rate applied under current GAAP, which is based on an expected investment yield from our current investment strategy, and the single-A discount rate that will be required as a part of the update. The most significant impact relates to our longest duration products. Our investment strategy reflects the illiquid nature of the majority of our liability cash flows and, as a result, the yields in our investment portfolios supporting the cash outflows required for these products are generally higher than a single-A yield. In addition, the discount rates currently applied to reserves for our longest duration products, such as long-term care, include an assumption for long-term yields rising to more historical levels. Our modified retrospective adoption is expected to result in an increase to net income during 2021 and 2022. We expect the increase in 2021 net income to be between approximately $145 million and $175 million, or between $0.70 and $0.85 per diluted per common share. We expect the increase in 2022 net income to be between approximately $80 million and $110 million, or $0.40 and $0.55 per diluted common share. The net favorable impact of the recast of our net income for 2021 and 2022 shown above is due primarily to the following changes: • Updating the lifetime cohort net premium ratios (lifetime loss ratio) for actual experience each reporting period will generally cause earnings patterns to be more consistent from period to period, with variances in experience reflected in earnings over the cohort lifetime. This will result in an unfavorable impact to income for 2021 and 2022. • Alignment of amortization of deferred acquisition costs to a constant level basis and modification of amortization periods to reflect the expected term of the related contracts could result in either higher or lower income for the affected product lines. This will result in a net favorable impact to income for 2021 and 2022. • Accelerated recognition of the provision for adverse deviation or other differences from current best estimate values for policies issued prior to the transition date and due to not establishing the provision for policies issued on or after the transition date will generally result in higher income most notably in the initial years after the transition date. This will result in a favorable impact to income for 2021 and 2022. • Establishing reserves for claims incurred on or after the transition date at interest rates prescribed by the update could result in either higher or lower income for the affected product lines depending on the policy issue date and the interest rate environment at that time. This will result in an unfavorable impact to income for 2021 and a favorable impact to income for 2022. • Updating cash flow assumptions could result in either higher or lower income. This will result in a favorable impact to income for 2021 and 2022. • Applying non-contemporaneous reinsurance accounting to the second phase of our Closed Block individual disability reinsurance transaction which was completed in the first quarter of 2021. The primary impacts of this change are: ◦ Reversing the increase in benefits and change in reserves for future benefits resulting from the realization of previously unrealized investment gains and losses previously recorded in AOCI that will be removed as of the transition date which will have a favorable impact on income for 2021. ◦ Remeasuring the ceded reserves as a separate cohort of reserves at interest rates prescribed by the update and the resulting change to the cost of reinsurance. The differential in the discount rate applied to the direct and ceded cohorts of business will result in an unfavorable impact to income for 2021 and 2022 partially offset by a decrease in the amortization of the cost of reinsurance as a result of a lower cost of reinsurance. We do not have products with market risk benefits. This update will also significantly expand our disclosures. ASU 2022-02, Financial Instruments—Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures The amendments in this update eliminate the troubled debt restructuring recognition and measurement guidance and instead require that an entity evaluate whether the modification represents a new loan or the continuation of an existing loan. The amendments also enhance the disclosure requirements related to certain modifications of receivables made to borrowers experiencing financial difficulty. In addition, the amendments in this update require that an entity disclose current-period gross write-offs by year of origination for financing receivables and net investment in leases. The amendments in this update should be applied prospectively, except for the transition method related to the recognition and measurement of troubled debt restructurings, for which an entity has the option to apply a modified retrospective transition method, resulting in a cumulative-effect adjustment to retained earnings in the period of adoption. This update is effective for periods beginning January 1, 2023, and we do not anticipate that the adoption of this update will have an effect on our financial position or results of operations but will expand our disclosures.

Fair Values of Financial Inst_2

Fair Values of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share	The following tables present additional information about our private equity partnerships, including commitments for additional investments which may or may not be funded: December 31, 2022 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 239.3 Not redeemable $ 90.9 35.7 Initial 2 year lock on each new investment / Quarterly after 2 year lock with 90 days notice 13.4 Total Private Credit 275.0 104.3 Private Equity (b) 453.6 Not redeemable 377.2 31.7 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 39.1 Total Private Equity 485.3 416.3 Real Assets (c) 373.9 Not redeemable 256.3 60.1 Quarterly / 90 days notice — Total Real Assets 434.0 256.3 Total Partnerships $ 1,194.3 $ 776.9 December 31, 2021 Investment Category Fair Value Redemption Term / Redemption Notice Unfunded Commitments (in millions of dollars) (in millions of dollars) Private Credit (a) $ 240.6 Not redeemable $ 143.7 38.8 Initial 2 year lock on each new investment / Quarterly after 2 year lock with 90 days notice 6.8 Total Private Credit 279.4 150.5 Private Equity (b) 365.8 Not redeemable 274.3 18.8 Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice 50.3 Total Private Equity 384.6 324.6 Real Assets (c) 256.2 Not redeemable 278.1 58.4 Quarterly / 90 days notice — Total Real Assets 314.6 278.1 Total Partnerships $ 978.6 $ 753.2 (a) Private Credit - The limited partnerships described in this category employ various investment strategies, generally providing direct lending or other forms of debt financing including first-lien, second-lien, mezzanine, and subordinated loans. The limited partnerships have credit exposure to corporates, physical assets, and/or financial assets within a variety of industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail) in North America and, to a lesser extent, outside of North America. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 55 percent in the next 3 years, 34 percent during the period from 3 to 5 years, 9 percent during the period from 5 to 10 years, and 2 percent during the period from 10 to 15 years. (b) Private Equity - The limited partnerships described in this category employ various strategies generally investing in controlling or minority control equity positions directly in companies and/or assets across various industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail), primarily in private markets within North America and, to a lesser extent, outside of North America. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 35 percent in the next 3 years, 19 percent during the period from 3 to 5 years, 40 percent during the period from 5 to 10 years, and 6 percent during the period from 10 to 15 years. (c) Real Assets - The limited partnerships described in this category employ various strategies, which include investing in the equity and/or debt financing of physical assets, including infrastructure (energy, power, water/wastewater, communications), transportation (including airports, ports, toll roads, aircraft, railcars) and real estate in North America, Europe, South America, and Asia. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 22 percent in the next 3 years, 28 percent during period from 3 to 5 years and 50 percent during the period from 5 to 10 years.
Fair Values by Fair Value Hierarchy Input Level	The following tables present information about financial instruments measured at fair value on a recurring basis by fair value level, based on the observability of the inputs used. December 31, 2022 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ 81.7 $ 416.5 $ — $ — $ 498.2 States, Municipalities, and Political Subdivisions 8.7 3,448.3 0.2 — 3,457.2 Foreign Governments — 827.1 — — 827.1 Public Utilities 160.1 4,796.8 — — 4,956.9 Mortgage/Asset-Backed Securities — 551.3 22.0 — 573.3 All Other Corporate Bonds 4,268.6 20,097.3 158.7 — 24,524.6 Redeemable Preferred Stocks — 3.5 — — 3.5 Total Fixed Maturity Securities 4,519.1 30,140.8 180.9 — 34,840.8 Other Long-term Investments Derivatives Forwards — 5.6 — — 5.6 Foreign Exchange Contracts — 83.5 — — 83.5 Total Derivatives — 89.1 — — 89.1 Perpetual Preferred and Equity Securities — 9.6 16.2 — 25.8 Private Equity Partnerships — — — 1,194.3 1,194.3 Total Other Long-term Investments — 98.7 16.2 1,194.3 1,309.2 Total Financial Instrument Assets Carried at Fair Value $ 4,519.1 $ 30,239.5 $ 197.1 $ 1,194.3 $ 36,150.0 Liabilities Other Liabilities Derivatives Forwards $ — $ 48.5 $ — $ — $ 48.5 Foreign Exchange Contracts — 25.5 — — 25.5 Embedded Derivative in Modified Coinsurance Arrangement — — 13.9 — 13.9 Total Derivatives — 74.0 13.9 — 87.9 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 74.0 $ 13.9 $ — $ 87.9 December 31, 2021 Level 1 Level 2 Level 3 NAV Total (in millions of dollars) Assets Fixed Maturity Securities United States Government and Government Agencies and Authorities $ — $ 580.1 $ — $ — $ 580.1 States, Municipalities, and Political Subdivisions — 4,714.1 13.4 — 4,727.5 Foreign Governments — 1,125.8 20.8 — 1,146.6 Public Utilities 230.8 6,140.7 44.5 — 6,416.0 Mortgage/Asset-Backed Securities — 451.1 187.2 — 638.3 All Other Corporate Bonds 3,288.7 25,673.2 861.5 — 29,823.4 Redeemable Preferred Stocks — 4.1 — — 4.1 Total Fixed Maturity Securities 3,519.5 38,689.1 1,127.4 — 43,336.0 Other Long-term Investments Derivatives Foreign Exchange Contracts — 39.5 — — 39.5 Total Derivatives — 39.5 — — 39.5 Perpetual Preferred and Equity Securities — 27.9 5.8 — 33.7 Private Equity Partnerships — — — 978.6 978.6 Total Other Long-term Investments — 67.4 5.8 978.6 1,051.8 Total Financial Instrument Assets Carried at Fair Value $ 3,519.5 $ 38,756.5 $ 1,133.2 $ 978.6 $ 44,387.8 Liabilities Other Liabilities Derivatives Foreign Exchange Contracts $ — $ 35.0 $ — $ — $ 35.0 Embedded Derivative in Modified Coinsurance Arrangement — — 30.1 — 30.1 Total Derivatives — 35.0 30.1 — 65.1 Total Financial Instrument Liabilities Carried at Fair Value $ — $ 35.0 $ 30.1 $ — $ 65.1
Changes in Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Unobservable Inputs	Changes in assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) are as follows: Year Ended December 31, 2022 Fair Value Beginning Total Realized and Purchases Sales/Maturities Level 3 Transfers Fair Value End of Change in Unrealized Earnings OCI Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities States, Municipalities, and Political Subdivisions $ 13.4 $ — $ (0.1) $ — $ — $ 0.3 $ (13.4) $ 0.2 $ (0.1) $ — Foreign Governments 20.8 — (0.8) — (20.0) — — — (0.8) — Public Utilities 44.5 — (2.8) — (12.8) 15.6 (44.5) — (2.8) — Mortgage/Asset-Backed Securities 187.2 — (0.3) 20.7 (10.6) — (175.0) 22.0 (0.3) — All Other Corporate Bonds 861.5 — (32.0) 25.3 (102.3) 161.9 (755.7) 158.7 (32.0) — Total Fixed Maturity Securities 1,127.4 — (36.0) 46.0 (145.7) 177.8 (988.6) 180.9 (36.0) — Perpetual Preferred and Equity Securities 5.8 3.0 — 7.1 — 0.3 — 16.2 — 3.0 Embedded Derivative in Modified Coinsurance Arrangement (30.1) 16.2 — — — — — (13.9) — 16.2 Year Ended December 31, 2021 Fair Value Beginning Total Realized and Purchases Sales/Maturities Level 3 Transfers Fair Value End of Change in Unrealized Earnings OCI Into Out of OCI Earnings (in millions of dollars) Fixed Maturity Securities States, Municipalities, and Political Subdivisions $ 15.5 $ — $ (2.1) $ — $ — $ — $ — $ 13.4 $ (2.1) $ — Foreign Governments 21.8 — (1.0) — — — — 20.8 (1.0) — Public Utilities 185.7 — (2.3) — (44.0) 36.0 (130.9) 44.5 (2.3) — Mortgage/Asset-Backed Securities 81.3 — (96.0) — (72.3) 274.2 — 187.2 (96.0) — All Other Corporate Bonds 943.1 — (24.6) 249.9 (80.2) 77.6 (304.3) 861.5 (24.6) — Total Fixed Maturity Securities 1,247.4 — (126.0) 249.9 (196.5) 387.8 (435.2) 1,127.4 (126.0) — Perpetual Preferred and Equity Securities 4.7 0.1 — 1.0 — — — 5.8 — 0.1 Embedded Derivative in Modified Coinsurance Arrangement (39.8) 9.7 — — — — — (30.1) — 9.7 Realized and unrealized investment gains and losses presented in the preceding tables represent gains and losses only for the time during which the applicable financial instruments were classified as Level 3. The transfers between levels resulted primarily from a change in observability of three inputs used to determine fair values of the securities transferred: (1) transactional data for new issuance and secondary trades, (2) broker/dealer quotes and pricing, primarily related to changes in the level of activity in the market and whether the market was considered orderly, and (3) comparable bond metrics from which to perform an analysis. For fair value measurements of financial instruments that were transferred either into or out of Level 3, we reflect the transfers using the fair value at the beginning of the period. We believe this allows for greater transparency, as all changes in fair value that arise during the reporting period of the transfer are disclosed as a component of our Level 3 reconciliation.
Quantitative Information Regarding Significant Unobservable Inputs	The table below provides quantitative information regarding the significant unobservable inputs used in Level 3 fair value measurements derived from internal models. Unobservable inputs for fixed maturity securities are weighted by the fair value of the securities. Certain securities classified as Level 3 are excluded from the table below due to limitations in our ability to obtain the underlying inputs used by external pricing sources. December 31, 2022 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 15.3 Market Approach Volatility of Credit Market Convention (a) (b) 5.41% - 5.41% / 5.41% Priced at Par Value Perpetual Preferred and Equity Securities 16.2 Market Approach Market Convention (b) Priced at Cost, Owner's Equity, or Most Recent Round Embedded Derivative in Modified Coinsurance Arrangement (13.9) Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (d) Actuarial Assumptions 0.6% December 31, 2021 Fair Value Valuation Method Unobservable Input Range/Weighted Average (in millions of dollars) Fixed Maturity Securities All Other Corporate Bonds - Private $ 111.8 Market Approach Volatility of Credit Lack of Marketability (a) (c) 6.30% - 6.30% / 6.30% 0.14% - 0.73% / 0.51% Perpetual Preferred and Equity Securities 5.8 Market Approach Market Convention (b) Priced at Cost or Owner's Equity Embedded Derivative in Modified Coinsurance Arrangement (30.1) Discounted Cash Flows Projected Liability Cash Flows Weighted Spread of Swap Curve (d) Actuarial Assumptions (a) Represents basis point adjustments for credit-specific factors (b) Represents a decision to price based on par value, cost, owner's equity, or the price of the most recent capital funding round when limited data is available (c) Represents basis point adjustments to apply a discount due to the illiquidity of an investment (d) Represents various actuarial assumptions required to derive the liability cash flows. Fair value of embedded derivative is most often driven by the change in the weighted average credit spread to the swap curve for the assets backing the hypothetical loan
Carrying Amount and Fair Value of Financial Instruments	The following table presents the carrying amounts and estimated fair values of our financial instruments not measured at fair value and indicates the level in the fair value hierarchy of the estimated fair value measurement based on the observability of the inputs used: December 31, 2022 Estimated Fair Value Level 1 Level 2 Level 3 Total Carrying Value (in millions of dollars) Assets Mortgage Loans $ — $ 2,159.5 $ — $ 2,159.5 $ 2,435.4 Policy Loans — — 3,677.0 3,677.0 3,601.2 Other Long-term Investments Miscellaneous Long-term Investments — 17.1 1.3 18.4 18.4 Total Financial Instrument Assets Not Carried at Fair Value $ — $ 2,176.6 $ 3,678.3 $ 5,854.9 $ 6,055.0 Liabilities Long-term Debt $ 2,288.9 $ 783.1 $ — $ 3,072.0 $ 3,427.8 Other Liabilities Unfunded Commitments — 0.7 — 0.7 0.7 Payable for Collateral on FHLB Funding Agreements — 99.1 — 99.1 99.1 Total Financial Instrument Liabilities Not Carried at Fair Value $ 2,288.9 $ 882.9 $ — $ 3,171.8 $ 3,527.6 December 31, 2021 Estimated Fair Value Level 1 Level 2 Level 3 Total Carrying Value (in millions of dollars) Assets Mortgage Loans $ — $ 2,677.8 $ — $ 2,677.8 $ 2,560.4 Policy Loans — — 3,807.1 3,807.1 3,662.9 Other Long-term Investments Miscellaneous Long-term Investments — 22.1 9.5 31.6 31.6 Total Financial Instrument Assets Not Carried at Fair Value $ — $ 2,699.9 $ 3,816.6 $ 6,516.5 $ 6,254.9 Liabilities Long-term Debt $ 2,237.3 $ 1,641.8 $ — $ 3,879.1 $ 3,442.2 Other Liabilities Unfunded Commitments — 0.7 — 0.7 0.7 Payable for Collateral on FHLB Funding Agreements — 160.9 — 160.9 160.9 Total Financial Instrument Liabilities Not Carried at Fair Value $ 2,237.3 $ 1,803.4 $ — $ 4,040.7 $ 3,603.8

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Amortized Cost and Fair Values of Securities by Security Type	At December 31, 2022 and 2021, all fixed maturity securities were classified as available-for-sale. The amortized cost and fair values of securities by security type are shown as follows: December 31, 2022 Amortized Cost, Gross of ACL (1) ACL (1) Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 503.8 $ — $ 20.3 $ 25.9 $ 498.2 States, Municipalities, and Political Subdivisions 4,006.0 — 87.1 635.9 3,457.2 Foreign Governments 908.1 — 34.9 115.9 827.1 Public Utilities 5,170.9 — 141.0 355.0 4,956.9 Mortgage/Asset-Backed Securities 592.1 — 8.2 27.0 573.3 All Other Corporate Bonds 26,640.3 — 452.1 2,567.8 24,524.6 Redeemable Preferred Stocks 4.0 — — 0.5 3.5 Total Fixed Maturity Securities $ 37,825.2 $ — $ 743.6 $ 3,728.0 $ 34,840.8 December 31, 2021 Amortized Cost, Gross of ACL (1) ACL (1) Gross Gross Fair (in millions of dollars) United States Government and Government Agencies and Authorities $ 460.1 $ — $ 120.1 $ 0.1 $ 580.1 States, Municipalities, and Political Subdivisions 4,150.2 — 584.2 6.9 4,727.5 Foreign Governments 952.0 — 215.3 20.7 1,146.6 Public Utilities 5,266.4 — 1,159.4 9.8 6,416.0 Mortgage/Asset-Backed Securities 587.9 — 50.4 — 638.3 All Other Corporate Bonds 25,966.1 — 3,919.9 62.6 29,823.4 Redeemable Preferred Stocks 4.0 — 0.1 — 4.1 Total Fixed Maturity Securities $ 37,386.7 $ — $ 6,049.4 $ 100.1 $ 43,336.0 (1) Allowance for Credit Losses
Distribution of the Maturity Dates for Fixed Maturity Securities	The following is a distribution of the maturity dates for fixed maturity securities. The maturity dates have not been adjusted for possible calls or prepayments. December 31, 2022 Amortized Cost, Net of ACL (1) Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 1,133.5 $ 2.9 $ 339.1 $ 5.7 $ 791.6 Over 1 year through 5 years 7,090.8 86.7 1,953.2 238.4 4,985.9 Over 5 years through 10 years 10,096.7 294.8 3,538.9 863.8 5,988.8 Over 10 years 18,912.1 351.0 5,013.2 2,593.1 11,656.8 37,233.1 735.4 10,844.4 3,701.0 23,423.1 Mortgage/Asset-Backed Securities 592.1 8.2 186.6 27.0 386.7 Total Fixed Maturity Securities $ 37,825.2 $ 743.6 $ 11,031.0 $ 3,728.0 $ 23,809.8 December 31, 2021 Amortized Cost, Net of ACL (1) Unrealized Gain Position Unrealized Loss Position Gross Gain Fair Value Gross Loss Fair Value (in millions of dollars) 1 year or less $ 767.3 $ 17.6 $ 756.0 $ 0.1 $ 28.9 Over 1 year through 5 years 6,613.2 540.2 7,050.5 6.0 96.9 Over 5 years through 10 years 10,614.3 1,453.3 10,905.0 26.0 1,136.6 Over 10 years 18,804.0 3,987.9 20,778.4 68.0 1,945.4 36,798.8 5,999.0 39,489.9 100.1 3,207.8 Mortgage/Asset-Backed Securities 587.9 50.4 609.0 — 29.3 Total Fixed Maturity Securities $ 37,386.7 $ 6,049.4 $ 40,098.9 $ 100.1 $ 3,237.1
Distribution by External Credit Rating for Fixed Maturity Securities	The following chart depicts an analysis of our fixed maturity security portfolio between investment-grade and below-investment-grade categories as of December 31, 2022: Gross Unrealized Loss Fair Value Gross Unrealized Gain Amount Percent of Total Gross Unrealized Loss (in millions of dollars) Investment-Grade $ 32,851.0 $ 734.6 $ 3,545.5 95.1 % Below-Investment-Grade 1,989.8 9.0 182.5 4.9 Total Fixed Maturity Securities $ 34,840.8 $ 743.6 $ 3,728.0 100.0 %
Debt Securities, Available-for-sale, Allowance for Credit Loss	The following tables present a rollforward of the allowance for credit losses on available-for-sale fixed maturity securities, which were classified as "public utilities" during year ended December 31, 2022 and "all other corporate bonds" during the year ended December 31, 2021, respectively. Year Ended December 31 2022 2021 (in millions of dollars) Balance, beginning of period $ — $ 6.8 Credit losses on securities for which credit losses were not previously recorded 4.6 — Change in allowance on securities with allowance recorded in previous period — 0.5 Change in allowance on securities disposed during the period (4.6) (7.3) Balance, end of period $ — $ —
Low Income Housing Tax Credits	The Company invests in tax credit partnerships primarily for the receipt of income tax credits and tax benefits derived from passive losses on the investments. Amounts recognized in the consolidated statements of income are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Income Tax Credits $ 8.0 $ 21.6 $ 33.2 Amortization, Net of Tax (5.9) (15.0) (21.9) Income Tax Benefit $ 2.1 $ 6.6 $ 11.3
Mortgage Loans by Property Type and Geographic Region	The carrying amount of mortgage loans by property type and geographic region are presented below. December 31 2022 2021 (in millions of dollars) Carrying Percent of Carrying Percent of Amount Total Amount Total Property Type Apartment $ 688.6 28.3 % $ 780.0 30.5 % Industrial 745.3 30.6 734.4 28.7 Office 423.0 17.4 467.2 18.2 Retail 534.5 21.9 533.3 20.8 Other 44.0 1.8 45.5 1.8 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % Region New England $ 52.4 2.2 % $ 54.9 2.1 % Mid-Atlantic 192.4 7.9 214.7 8.4 East North Central 313.0 12.9 298.4 11.7 West North Central 181.4 7.4 193.1 7.5 South Atlantic 539.3 22.1 582.1 22.7 East South Central 101.8 4.2 120.7 4.7 West South Central 212.6 8.7 243.2 9.6 Mountain 298.7 12.3 290.6 11.3 Pacific 543.8 22.3 562.7 22.0 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 %
Schedule of Participating Mortgage Loans by Internal Credit Rating and Loan to Value	The following tables present information about mortgage loans by the applicable credit quality indicators: December 31 2022 2021 (in millions of dollars) Carrying Amount Percent of Total Carrying Amount Percent of Total Internal Rating AA $ 92.3 3.8 % $ 27.3 1.1 % A 843.9 34.6 709.6 27.7 BBB 1,458.0 59.9 1,802.6 70.4 BB 41.2 1.7 20.9 0.8 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % Loan-to-Value Ratio (1) <= 65% $ 1,389.6 57.0 % $ 1,346.1 52.6 % > 65% <= 75% 937.2 38.5 1,076.8 42.0 > 75% <= 85% 75.0 3.1 114.9 4.5 > 85% 33.6 1.4 22.6 0.9 Total $ 2,435.4 100.0 % $ 2,560.4 100.0 % (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property
Mortgage Loans by Credit Quality Indicators	The following table presents the amortized cost of our mortgage loans by year of origination and credit quality indicators for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 Prior to 2018 2018 2019 2020 2021 2022 Total (in millions of dollars) Internal Rating AA $ 53.8 $ 27.5 $ 11.1 $ — $ — $ — $ 92.4 A 485.0 123.3 96.8 35.9 80.6 24.0 845.6 BBB 534.0 219.8 236.9 134.0 275.8 64.6 1,465.1 BB 35.7 5.9 — — — — 41.6 Total Amortized Cost 1,108.5 376.5 344.8 169.9 356.4 88.6 2,444.7 Allowance for credit losses (4.3) (1.8) (1.3) (0.6) (0.8) (0.5) (9.3) Carrying Amount $ 1,104.2 $ 374.7 $ 343.5 $ 169.3 $ 355.6 $ 88.1 $ 2,435.4 Loan-to-Value Ratio (1) <=65% $ 782.6 $ 189.0 $ 193.9 $ 81.3 $ 128.9 $ 16.9 $ 1,392.6 >65<=75% 230.2 181.6 150.9 80.1 227.5 71.7 942.0 >75%<=85% 67.5 — — 8.5 — — 76.0 >85% 28.2 5.9 — — — — 34.1 Total Amortized Cost 1,108.5 376.5 344.8 169.9 356.4 88.6 2,444.7 Allowance for credit losses (4.3) (1.8) (1.3) (0.6) (0.8) (0.5) (9.3) Carrying Amount $ 1,104.2 $ 374.7 $ 343.5 $ 169.3 $ 355.6 $ 88.1 $ 2,435.4 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property Year Ended December 31, 2021 Prior to 2017 2017 2018 2019 2020 2021 Total (in millions of dollars) Internal Rating AA $ 3.3 $ — $ 24.0 $ — $ — $ — $ 27.3 A 414.6 68.0 71.1 28.9 17.6 110.6 710.8 BBB 561.2 227.3 283.3 331.9 163.1 242.6 1,809.4 BB 5.0 10.2 6.0 — — — 21.2 Total Amortized Cost 984.1 305.5 384.4 360.8 180.7 353.2 2,568.7 Allowance for credit losses (2.6) (1.4) (1.4) (1.4) (0.7) (0.8) (8.3) Carrying Amount $ 981.5 $ 304.1 $ 383.0 $ 359.4 $ 180.0 $ 352.4 $ 2,560.4 Loan-to-Value Ratio (1) <=65% $ 779.1 $ 146.9 $ 163.0 $ 80.7 $ 54.3 $ 124.7 $ 1,348.7 >65<=75% 115.7 115.4 215.4 280.1 126.4 228.5 1,081.5 >75%<=85% 89.3 26.3 — — — — 115.6 >85% — 16.9 6.0 — — — 22.9 Total Amortized Cost 984.1 305.5 384.4 360.8 180.7 353.2 2,568.7 Allowance for credit losses (2.6) (1.4) (1.4) (1.4) (0.7) (0.8) (8.3) Carrying Amount $ 981.5 $ 304.1 $ 383.0 $ 359.4 $ 180.0 $ 352.4 $ 2,560.4 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property
Financing Receivable, Allowance for Credit Loss	The following tables present a roll forward of allowance for expected credit losses by loan-to-value ratio for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio (1) <=65% $ 2.6 $ 0.4 $ — $ — $ 3.0 >65<=75% 4.7 — — — 4.7 >75%<=85% 0.7 0.4 — — 1.1 >85% 0.3 0.2 — — 0.5 Total $ 8.3 $ 1.0 $ — $ — $ 9.3 Year Ended December 31, 2021 Beginning of Period Current Period Provisions Write-Offs Recoveries End of Period (in millions of dollars) Loan-to-Value Ratio (1) <=65% $ 3.4 $ (0.8) $ — $ — $ 2.6 >65<=75% 7.3 (2.6) — — 4.7 >75%<=85% 1.3 (0.6) — — 0.7 >85% 1.1 (0.8) — — 0.3 Total $ 13.1 $ (4.8) $ — $ — $ 8.3 (1) Loan-to Value Ratio utilizes the most recent internal appraisal of the property
Remaining Contractual Maturity of Securities Lending Agreements	The remaining contractual maturities of our securities lending agreements disaggregated by class of collateral pledged are as follows: December 31 2022 2021 Overnight and Continuous (in millions of dollars) Borrowings United States Government and Government Agencies and Authorities $ 0.3 $ 0.1 State, Municipalities, and Political Subdivisions — 0.1 Public Utilities 6.3 3.1 All Other Corporate Bonds 81.9 91.5 Total Borrowings $ 88.5 $ 94.8 Gross Amount of Recognized Liability for Securities Lending Transactions 88.5 94.8 Amounts Related to Agreements Not Included in Offsetting Disclosure Contained Herein $ — $ —
Federal Home Loan Bank Common Stock Carrying Amounts, Amounts Posted, and Advances Received	The carrying value of common stock owned, collateral posted, and advances received are as follows: December 31 2022 2021 (in millions of dollars) Carrying Value of FHLB Common Stock $ 17.1 $ 22.1 Advances from FHLB 99.1 160.9 Carrying Value of Collateral Posted to FHLB Fixed Maturity Securities $ 527.1 $ 786.1 Commercial Mortgage Loans 801.9 930.0 Total Carrying Value of Collateral Posted to FHLB $ 1,329.0 $ 1,716.1
Schedule of Financial Instrument and Derivative Offsetting	Shown below are our financial instruments that either meet the accounting requirements that allow them to be offset in our balance sheets or that are subject to an enforceable master netting arrangement or similar agreement. Our accounting policy is to not offset these financial instruments in our balance sheets. Net amounts disclosed below have been reduced by the amount of collateral pledged to or received from our counterparties. December 31, 2022 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 89.1 $ — $ 89.1 $ (38.0) $ (49.4) $ 1.7 Securities Lending 152.4 — 152.4 (63.9) (88.5) — Total $ 241.5 $ — $ 241.5 $ (101.9) $ (137.9) $ 1.7 Financial Liabilities: Derivatives $ 74.0 $ — $ 74.0 $ (73.2) $ — $ 0.8 Securities Lending 88.5 — 88.5 (88.5) — — Total $ 162.5 $ — $ 162.5 $ (161.7) $ — $ 0.8 December 31, 2021 Gross Amount Gross Amount Not of Recognized Gross Amount Net Amount Offset in Balance Sheet Financial Offset in Presented in Financial Cash Net Instruments Balance Sheet Balance Sheet Instruments Collateral Amount (in millions of dollars) Financial Assets: Derivatives $ 39.5 $ — $ 39.5 $ (9.8) $ (28.4) $ 1.3 Securities Lending 283.7 — 283.7 (188.9) (94.8) — Total $ 323.2 $ — $ 323.2 $ (198.7) $ (123.2) $ 1.3 Financial Liabilities: Derivatives $ 35.0 $ — $ 35.0 $ (34.0) $ — $ 1.0 Securities Lending 94.8 — 94.8 (94.8) — — Total $ 129.8 $ — $ 129.8 $ (128.8) $ — $ 1.0
Net Investment Income	Net investment income reported in our consolidated statements of income is presented below. Year Ended December 31 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities $ 1,849.8 $ 1,888.2 $ 2,164.0 Derivatives 57.8 68.6 78.7 Mortgage Loans 101.5 105.0 108.9 Policy Loans 20.0 19.7 20.0 Other Long-term Investments Perpetual Preferred Securities 1 5.0 6.9 (2.1) Private Equity Partnerships 2 110.1 165.4 19.8 Other 9.4 5.5 3.9 Short-term Investments 20.0 1.3 10.5 Gross Investment Income 2,173.6 2,260.6 2,403.7 Less Investment Expenses 39.4 35.1 30.6 Less Investment Income on Participation Fund Account Assets 12.0 12.3 12.4 Net Investment Income $ 2,122.2 $ 2,213.2 $ 2,360.7 1 The net unrealized gain (loss) recognized in net investment income for the year ended December 31, 2022 related to perpetual preferred securities still held at December 31, 2022 was $2.8 million. The net unrealized gain (loss) recognized in net investment income for the years ended December 31, 2021 and 2020 related to perpetual preferred securities still held at year-end was $4.4 million and $(4.6) million, respectively 2 Represents a net unrealized gain for the year ended December 31, 2022 related to private equity partnerships still held at December 31, 2022 of $124.1 million, reduced by net management fees and partnership expenses of $(14.0) million. For the years ended December 31, 2021 and 2020, the net unrealized gain related to private equity partnerships still held at year-end was $177.7 million and $29.1 million, respectively, reduced by net management fees and partnership expenses of $(12.3) million and $(9.3) million, respectively. See Note 2 for further discussion of private equity partnerships.	[1]
Realized Investment Gains and Losses Reported in Consolidated Statements of Income	Investment Gain and Loss Investment gains and losses are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities Gross Gains on Sales 1 $ 2.3 $ 76.2 $ 1,332.8 Gross Losses on Sales (28.8) (11.5) (20.3) Credit Losses (4.6) (9.3) (53.6) Mortgage Loans and Other Invested Assets Gross Gains on Sales 1.4 5.8 1.9 Gross Losses on Sales — — (0.3) Impairment Loss — — (36.6) Change in Allowance for Credit Losses (1.0) 4.7 (4.6) Embedded Derivative in Modified Coinsurance Arrangement 16.2 9.7 (17.0) All Other Derivatives 2.6 3.1 (2.5) Foreign Currency Transactions (3.8) (2.0) (0.7) Net Investment Gain (Loss) $ (15.7) $ 76.7 $ 1,199.1 1 Gross gains on sales of fixed maturity securities for the year ended December 31, 2021 includes gains of $67.6 million as a result of the second phase of the reinsurance transaction that we completed during the first quarter of 2021. Gross gains on sales of fixed maturity securities for the year ended December 31, 2020 includes gains of $1,302.3 million as a result of the first phase of the reinsurance transaction that we completed during the fourth quarter of 2020. See Note 12 for further discussion.
Schedule of Unrealized Loss on Investments	The following charts indicate the length of time our fixed maturity securities have been in a gross unrealized loss position. December 31, 2022 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 246.6 $ 22.6 $ 12.2 $ 3.3 States, Municipalities, and Political Subdivisions 1,920.1 476.1 346.6 159.8 Foreign Governments 160.1 47.9 176.9 68.0 Public Utilities 2,242.2 252.0 255.2 103.0 Mortgage/Asset-Backed Securities 386.6 27.0 0.1 — All Other Corporate Bonds 15,865.6 1,799.7 2,194.1 768.1 Redeemable Preferred Stocks 3.5 0.5 — — Total Fixed Maturity Securities $ 20,824.7 $ 2,625.8 $ 2,985.1 $ 1,102.2 December 31, 2021 Less Than 12 Months 12 Months or Greater Fair Gross Fair Gross (in millions of dollars) United States Government and Government Agencies and Authorities $ 9.3 $ 0.1 $ — $ — States, Municipalities, and Political Subdivisions 326.4 6.9 0.4 — Foreign Governments 234.4 18.9 10.7 1.8 Public Utilities 263.3 9.1 17.6 0.7 Mortgage/Asset-Backed Securities 29.2 — 0.1 — All Other Corporate Bonds 2,146.3 51.6 199.4 11.0 Total Fixed Maturity Securities $ 3,008.9 $ 86.6 $ 228.2 $ 13.5
[1]Represents a net unrealized gain for the year ended December 31, 2022 related to private equity partnerships still held at December 31, 2022 of $124.1 million, reduced by net management fees and partnership expenses of $(14.0) million. For the years ended December 31, 2021 and 2020, the net unrealized gain related to private equity partnerships still held at year-end was $177.7 million and $29.1 million, respectively, reduced by net management fees and partnership expenses of $(12.3) million and $(9.3) million, respectively. See Note 2 for further discussion of private equity partnerships.

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Nature and Amount of Collateral Received From and Posted To Derivative Counterparty	The table below summarizes the nature and amount of collateral received from and posted to our derivative counterparties. December 31 2022 2021 (in millions of dollars) Carrying Value of Collateral Received from Counterparties Cash $ 49.4 $ 32.0 Carrying Value of Collateral Posted to Counterparties Cash $ 5.1 $ — Fixed Maturity Securities 39.6 27.6 $ 44.7 $ 27.6
Fair Value Hedges Carrying Amount of Hedged Assets and Liabilities and Cumulative Basis Adjustments	The following table summarizes the carrying amount of hedged assets and the related cumulative basis adjustments related to our fair value hedges: Carrying Amount of Hedged Assets Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets December 31, 2022 December 31, 2021 December 31, 2022 December 31, 2021 (in millions of dollars) Fixed maturity securities: Receive fixed functional currency interest, pay fixed foreign currency interest $ 394.4 $ 466.3 $ (24.8) $ 2.0
Location and Fair Values of Derivative Financial Instruments	The following tables summarize the notional amounts and fair values of derivative financial instruments, as reported in our consolidated balance sheets. Derivative assets are included in other long-term investments, while derivative liabilities are included in other liabilities within our consolidated balance sheets. The notional amounts represent the basis upon which our counterparty pay and receive amounts are calculated. December 31, 2022 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Forward Benchmark Interest Rate Locks $ 764.0 $ 1.6 $ 48.4 Foreign Currency Interest Rate Swaps 168.9 17.5 3.1 Total Cash Flow Hedges 932.9 19.1 51.5 Fair Value Hedges Foreign Currency Interest Rate Swaps 557.8 66.0 5.4 Total Designated as Hedging Instruments $ 1,490.7 $ 85.1 $ 56.9 Not Designated as Hedging Instruments Foreign Currency Forwards $ 54.3 $ 4.0 $ 0.1 Foreign Currency Interest Rate Swaps 132.0 — 17.0 Total Return Swaps 76.9 — — Embedded Derivative in Modified Coinsurance Arrangement — — 13.9 Total Not Designated as Hedging Instruments $ 263.2 $ 4.0 $ 31.0 Total Derivatives $ 1,753.9 $ 89.1 $ 87.9 December 31, 2021 Derivative Assets Derivative Liabilities Notional Fair Fair (in millions of dollars) Designated as Hedging Instruments Cash Flow Hedges Foreign Currency Interest Rate Swaps $ 181.3 $ 16.2 $ 7.0 Fair Value Hedges Foreign Currency Interest Rate Swaps 498.5 21.9 5.7 Total Designated as Hedging Instruments $ 679.8 $ 38.1 $ 12.7 Not Designated as Hedging Instruments Credit Default Swaps $ 11.6 $ — $ — Foreign Currency Forwards 41.7 — — Foreign Currency Interest Rate Swaps 148.2 1.4 22.3 Total Return Swaps 89.2 — — Embedded Derivative in Modified Coinsurance Arrangement — — 30.1 Total Not Designated as Hedging Instruments $ 290.7 $ 1.4 $ 52.4 Total Derivatives $ 970.5 $ 39.5 $ 65.1
Location of Gains and Losses on Derivative Instruments Designated as Cash Flow Hedging Instruments	The following tables summarize the location of gains and losses of derivative financial instruments designated as hedging instruments, as reported in our consolidated statements of income. Year Ended December 31, 2022 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 2,122.2 $ (15.7) $ 188.5 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged items 200.0 — 2.9 Derivatives Designated as Hedging Instruments 51.0 — — Foreign Exchange Contracts: Hedged items 12.3 (2.3) — Derivatives Designated as Hedging Instruments (0.8) 1.8 — Forward Benchmark Interest Rate Locks: Hedged items 0.5 — — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged items 11.6 (26.8) — Derivatives Designated as Hedging Instruments 7.3 26.8 — Year Ended December 31, 2021 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 2,213.2 $ 76.7 $ 185.0 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged items 220.4 2.7 29.2 Derivatives Designated as Hedging Instruments 64.6 2.0 5.0 Foreign Exchange Contracts: Hedged items 13.0 (0.1) — Derivatives Designated as Hedging Instruments 1.8 (0.1) — Gain (Loss) on Fair Value Hedging Relationships Foreign Exchange Contracts: Hedged items 9.8 (22.3) — Derivatives Designated as Hedging Instruments 4.6 22.3 — Year Ended December 31, 2020 Net Investment Income Net Investment Gain (Loss) Interest and Debt Expense (in millions of dollars) Total Income and Expense Presented in the Consolidated Statements of Income of Which Hedged Items are Recorded $ 2,360.7 $ 1,199.1 $ 188.2 Gain (Loss) on Cash Flow Hedging Relationships Interest Rate Swaps: Hedged items 286.1 397.7 29.2 Derivatives Designated as Hedging Instruments 75.9 32.0 1.7 Foreign Exchange Contracts: Hedged items 12.1 (0.1) — Derivatives Designated as Hedging Instruments 2.5 0.1 — Gain (Loss) on Fair Value Hedging Relationships Interest Rate Swaps: Hedged items — (0.6) 10.1 Derivatives Designated as Hedging Instruments — 0.6 (0.9) Foreign Exchange Contracts: Hedged items 7.1 23.3 — Derivatives Designated as Hedging Instruments 2.8 (23.3) —
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss)	The following table summarizes the location of gains and losses of derivative financial instruments designated as cash flow hedging instruments, as reported in our consolidated statements of comprehensive income (loss). Year Ended December 31 2022 2021 2020 (in millions of dollars) Gain (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives Forwards $ (49.8) $ (0.6) $ — Foreign Exchange Contracts 7.4 2.2 (5.4) Total $ (42.4) $ 1.6 $ (5.4)
Gains and Losses on Derivatives Not Designated as Hedging Instruments	The following table summarizes the location of gains and losses on our derivatives not designated as hedging instruments, as reported in our consolidated statements of income. Year Ended December 31 2022 2021 2020 (in millions of dollars) Net Investment Gain (Loss) Credit Default Swaps $ — $ (0.3) $ (0.5) Foreign Exchange Contracts 2.7 3.4 (2.0) Embedded Derivative in Modified Coinsurance Arrangement 16.2 9.7 (17.0) Total $ 18.9 $ 12.8 $ (19.5) Other Expenses (Gain) Loss on Total Return Swaps $ 18.9 $ (8.5) $ —

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Components of our accumulated other comprehensive income (loss), after tax, and related changes are as follows: Net Unrealized Gain (Loss) on Securities Net Gain (Loss) on Hedges Foreign Currency Translation Adjustment Unrecognized Pension and Postretirement Benefit Costs Total (in millions of dollars) Balances at December 31, 2019 $ 615.9 $ 187.8 $ (281.6) $ (484.8) $ 37.3 Other Comprehensive Income (Loss) Before Reclassifications 405.6 (5.7) 20.3 (60.8) 359.4 Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 46.2 (84.3) — 15.6 (22.5) Net Other Comprehensive Income (Loss) 451.8 (90.0) 20.3 (45.2) 336.9 Balances at December 31, 2020 1,067.7 97.8 (261.3) (530.0) 374.2 Other Comprehensive Income (Loss) Before Reclassifications (169.9) 14.7 (12.6) 116.3 (51.5) Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 64.4 (50.7) — 17.7 31.4 Net Other Comprehensive Income (Loss) (105.5) (36.0) (12.6) 134.0 (20.1) Balances at December 31, 2021 962.2 61.8 (273.9) (396.0) 354.1 Other Comprehensive Income (Loss) Before Reclassifications (3,009.2) (30.4) (115.2) 49.7 (3,105.1) Amounts Reclassified from Accumulated Other Comprehensive Income or Loss 23.2 (41.0) — 12.2 (5.6) Net Other Comprehensive Income (Loss) (2,986.0) (71.4) (115.2) 61.9 (3,110.7) Balances at December 31, 2022 $ (2,023.8) $ (9.6) $ (389.1) $ (334.1) $ (2,756.6)
Schedule of Components of Unrealized Gain (Loss) on Securities	The net unrealized gain (loss) on securities consists of the following components: December 31 Change for the Year Ended December 31 2022 2021 2020 2019 2022 2021 2020 (in millions of dollars) Fixed Maturity Securities $ (2,984.4) $ 5,949.3 $ 7,597.6 $ 6,364.4 $ (8,933.7) $ (1,648.3) $ 1,233.2 Deferred Acquisition Costs 11.3 (70.4) (85.1) (62.7) 81.7 14.7 (22.4) Reserves for Future Policy and Contract Benefits 566.7 (4,659.5) (6,225.6) (5,803.1) 5,226.2 1,566.1 (422.5) Reinsurance Recoverable (18.1) 132.1 200.2 424.7 (150.2) (68.1) (224.5) Income Tax 400.7 (389.3) (419.4) (307.4) 790.0 30.1 (112.0) Total $ (2,023.8) $ 962.2 $ 1,067.7 $ 615.9 $ (2,986.0) $ (105.5) $ 451.8
Schedule of Reclassification out of Accumulated Other Comprehensive Income (Loss)	Amounts reclassified from accumulated other comprehensive income (loss) were recognized in our consolidated statements of income as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Net Unrealized Loss on Securities Net Investment Gain (Loss) Gain (Loss) on Sales on Securities $ (24.8) $ 60.8 $ 1,279.7 Credit Losses on Fixed Maturity Securities (4.6) (9.3) (53.6) Loss on Benefits and Change in Reserves for Future Benefits — (133.1) (1,284.5) (29.4) (81.6) (58.4) Income Tax Benefit (6.2) (17.2) (12.2) Total $ (23.2) $ (64.4) $ (46.2) Net Gain (Loss) on Hedges Net Investment Income Gain on Interest Rate Swaps and Forwards $ 51.1 $ 60.6 $ 74.1 Gain (Loss) on Foreign Exchange Contracts (1.0) 1.7 2.0 Net Investment Gain (Loss) Gain on Interest Rate Swaps — 2.0 32.0 Gain (Loss) on Foreign Exchange Contracts 1.8 (0.1) 0.1 Interest and Debt Expense Loss on Interest Rate Swaps — — (1.5) 51.9 64.2 106.7 Income Tax Expense 10.9 13.5 22.4 Total $ 41.0 $ 50.7 $ 84.3 Unrecognized Pension and Postretirement Benefit Costs Other Expenses Amortization of Net Actuarial Loss $ (15.7) $ (22.6) $ (19.8) Amortization of Prior Service Credit 0.2 0.2 0.1 Curtailment Gain — — (0.1) (15.5) (22.4) (19.8) Income Tax Benefit (3.3) (4.7) (4.2) Total $ (12.2) $ (17.7) $ (15.6)

Liability for Unpaid Claims a_2

Liability for Unpaid Claims and Claim Adjustment Expenses (Tables)	12 Months Ended
	Dec. 31, 2022
Insurance [Abstract]
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense	Changes in the liability for unpaid claims and claim adjustment expenses are as follows: 2022 2021 2020 (in millions of dollars) Balance at January 1 $ 23,664.7 $ 24,180.2 $ 23,076.7 Less Reinsurance Recoverable 8,697.8 8,378.9 2,246.8 Net Balance at January 1 14,966.9 15,801.3 20,829.9 Incurred Related to Current Year 6,721.3 7,252.6 6,327.8 Prior Years Interest 595.6 683.4 997.8 All Other Incurred (646.0) (719.5) 878.7 Foreign Currency (235.9) (23.4) 65.9 Total Incurred 6,435.0 7,193.1 8,270.2 Paid Related to Current Year (3,062.9) (3,263.4) (2,727.0) Prior Years (3,786.0) (3,774.1) (4,430.3) Total Paid (6,848.9) (7,037.5) (7,157.3) Reserves Ceded Pursuant to Reinsurance Transaction — (990.0) (6,141.5) Net Balance at December 31 14,553.0 14,966.9 15,801.3 Plus Reinsurance Recoverable 8,279.8 8,697.8 8,378.9 Balance at December 31 $ 22,832.8 $ 23,664.7 $ 24,180.2
Reconciliation of Policy and Contract Benefits and Reserves for Future Policy and Contract Benefits to Balance Sheet Amounts	A reconciliation of policy and contract benefits and reserves for future policy and contract benefits as reported in our consolidated balance sheets to the liability for unpaid claims and claim adjustment expenses is as follows: December 31 2022 2021 2020 (in millions of dollars) Policy and Contract Benefits $ 1,839.8 $ 1,907.7 $ 1,855.4 Reserves for Future Policy and Contract Benefits 42,330.2 48,007.5 49,653.0 Total 44,170.0 49,915.2 51,508.4 Less: Life Reserves for Future Policy and Contract Benefits 8,428.5 8,457.1 8,371.7 Accident and Health Active Life Reserves 13,475.4 13,133.9 12,730.9 Adjustment Related to Unrealized Investment Gains (Losses) (566.7) 4,659.5 6,225.6 Liability for Unpaid Claims and Claim Adjustment Expenses $ 22,832.8 $ 23,664.7 $ 24,180.2

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Total income tax expense (benefit) is allocated as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Net Income $ 317.2 $ 238.8 $ 171.0 Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) Change in Net Unrealized Gain (Loss) on Securities Before Adjustment (1,890.8) (346.9) 250.2 Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance 1,100.8 316.8 (138.2) Change in Net Gain (Loss) on Hedges (19.2) (9.8) (23.8) Change in Foreign Currency Translation Adjustment (0.1) 4.2 (4.3) Change in Unrecognized Pension and Postretirement Benefit Costs 18.9 42.1 (34.8) Total $ (473.2) $ 245.2 $ 220.1
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the income tax provision at the U.S. federal statutory rate to the income tax rate as reported in our consolidated statements of income is as follows: Year Ended December 31 2022 2021 2020 Statutory Income Tax 21.0 % 21.0 % 21.0 % Net Operating Loss Carryback — (0.7) (3.8) Tax Exempt Income (1.1) (1.1) (0.8) Tax Credits (0.3) (0.9) (1.3) Policyholder Reserves (1.9) 2.4 0.7 Other Items, Net 1.7 1.8 1.9 Effective Tax 19.4 % 22.5 % 17.7 %
Schedule of Deferred Tax Assets and Liabilities	Our net deferred tax asset (liability) consists of the following. December 31 2022 2021 (in millions of dollars) Deferred Tax Asset Invested Assets $ 664.9 $ — Reserves — 889.7 Employee Benefits 158.3 176.6 Other 34.4 57.5 Gross Deferred Tax Asset 857.6 1,123.8 Less: Valuation Allowance 10.3 12.7 Net Deferred Tax Asset 847.3 1,111.1 Deferred Tax Liability Deferred Acquisition Costs 113.1 134.9 Fixed Assets 48.9 71.1 Invested Assets — 1,144.9 Reserves 43.2 — Cost of Reinsurance 156.8 171.6 Other 44.7 47.0 Gross Deferred Tax Liability 406.7 1,569.5 Net Deferred Tax Asset (Liability) $ 440.6 $ (458.4)
Schedule of Income before Income Tax, Domestic and Foreign	Our consolidated statements of income include amounts subject to both domestic and foreign taxation. The income and related tax expense (benefit) are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Income Before Tax Domestic $ 1,492.8 $ 957.0 $ 924.7 Foreign 138.6 106.0 39.3 Total $ 1,631.4 $ 1,063.0 $ 964.0 Current Tax Expense (Benefit) Federal $ 306.5 $ 180.7 $ (98.4) State and Local 12.7 2.6 1.5 Foreign 154.3 29.5 (19.7) Total 473.5 212.8 (116.6) Deferred Tax Expense (Benefit) Federal 20.9 13.3 250.5 State and Local 1.1 (2.2) 1.0 Foreign (178.3) 14.9 36.1 Total (156.3) 26.0 287.6 Total Tax Expense $ 317.2 $ 238.8 $ 171.0
Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible	Our consolidated statements of income include the following changes in unrecognized tax benefits. December 31 2022 2021 2020 (in millions of dollars) Balance at Beginning of Year $ 198.8 $ 219.7 $ 241.0 Decreases for Tax Positions Related to Prior Years (21.0) (20.9) (21.0) Lapse of the Applicable Statute of Limitations (0.4) — (0.3) Balance at End of Year 177.4 198.8 219.7 Less Tax Attributable to Temporary Items Included Above (63.5) (84.7) (105.9) Total Unrecognized Tax Benefits That if Recognized Would Affect the Effective Tax Rate $ 113.9 $ 114.1 $ 113.8

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Schedule of Debt	Debt consists of the following: December 31 2022 2021 Interest Rates Maturities (in millions of dollars) Outstanding Principal Senior Notes issued 1998 6.750 - 7.250% 2028 $ 335.8 $ 335.8 Senior Notes issued 2002 7.375% 2032 39.5 39.5 Senior Notes issued 2012 and 2016 5.750% 2042 500.0 500.0 Senior Notes issued 2014 4.000% 2024 — 350.0 Senior Notes issued 2015 3.875% 2025 275.0 275.0 Senior Notes issued 2019 4.000% 2029 400.0 400.0 Senior Notes issued 2019 4.500% 2049 450.0 450.0 Senior Notes issued 2021 4.125% 2051 600.0 600.0 Medium-term Notes issued 1990 - 1996 7.000 - 7.190% 2023 - 2028 18.5 20.5 Junior Subordinated Debt Securities issued 1998 7.405% 2038 189.7 203.7 Junior Subordinated Debt Securities issued 2018 6.250% 2058 300.0 300.0 Term Loan issued 2022 Variable 2027 350.0 — Less: Unamortized Net Premium 2.5 2.3 Unamortized Debt Issuance Costs (33.2) (34.6) Total Long-term Debt $ 3,427.8 $ 3,442.2 Short-term Debt Medium-term Notes Issued 1990 7.000% 2023 2.0 — Total Debt $ 3,429.8 $ 3,442.2

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans
Schedule of Changes in Projected Benefit Obligations and Fair Value of Plan Assets	The following table provides the changes in the benefit obligation and fair value of plan assets and the funded status of the plans. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 (in millions of dollars) Change in Benefit Obligation Benefit Obligation at Beginning of Year $ 2,207.5 $ 2,277.2 $ 278.3 $ 300.0 $ 110.3 $ 120.5 Service Cost 7.7 9.6 — — — — Interest Cost 67.2 65.0 5.0 4.2 3.0 3.0 Plan Participant Contributions — — — — 0.1 0.1 Actuarial Gain (1) (604.1) (57.9) (92.4) (18.0) (19.4) (3.0) Benefits and Expenses Paid (92.8) (86.4) (5.4) (5.2) (10.1) (10.3) Change in Foreign Exchange Rates — — (27.6) (2.7) — — Benefit Obligation at End of Year $ 1,585.5 $ 2,207.5 $ 157.9 $ 278.3 $ 83.9 $ 110.3 Accumulated Benefit Obligation at December 31 $ 1,585.5 $ 2,207.5 $ 158.0 $ 276.5 N/A N/A Change in Fair Value of Plan Assets Fair Value of Plan Assets at Beginning of Year $ 1,801.7 $ 1,710.9 $ 303.7 $ 294.1 $ 9.0 $ 9.3 Actual Return on Plan Assets (410.6) 167.6 (128.4) 18.0 0.1 0.1 Employer Contributions 10.0 9.6 — — 9.4 9.8 Plan Participant Contributions — — — — 0.1 0.1 Benefits and Expenses Paid (92.8) (86.4) (5.4) (5.2) (10.1) (10.3) Change in Foreign Exchange Rates — — (29.4) (3.2) — — Fair Value of Plan Assets at End of Year $ 1,308.3 $ 1,801.7 $ 140.5 $ 303.7 $ 8.5 $ 9.0 Underfunded (Overfunded) Status $ 277.2 $ 405.8 $ 17.4 $ (25.4) $ 75.4 $ 101.3 (1) The actuarial gains recognized in 2022 and 2021 for the U.S., OPEB, and U.K. plans were primarily driven by increases in the discount rate assumption.
Schedule of Amounts Recognized in Balance Sheet	The amounts recognized in our consolidated balance sheets for our pension and OPEB plans at December 31, 2022 and 2021 are as follows. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 (in millions of dollars) Current Liability $ 8.8 $ 8.4 $ — $ — $ 1.1 $ 1.4 Noncurrent Liability 268.4 397.4 17.4 — 74.3 99.9 Noncurrent Asset — — — (25.4) — — Underfunded (Overfunded) Status $ 277.2 $ 405.8 $ 17.4 $ (25.4) $ 75.4 $ 101.3 Unrecognized Pension and Postretirement Benefit Costs Net Actuarial Gain (Loss) $ (517.8) $ (621.8) $ (83.7) $ (42.9) $ 31.6 $ 13.6 Prior Service Credit (Cost) (0.6) (0.6) (0.2) (0.2) 2.5 2.7 (518.4) (622.4) (83.9) (43.1) 34.1 16.3 Income Tax 213.5 239.2 19.5 9.1 1.1 4.9 Total Included in Accumulated Other Comprehensive Income (Loss) $ (304.9) $ (383.2) $ (64.4) $ (34.0) $ 35.2 $ 21.2
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	The following table provides the changes recognized in other comprehensive income for the years ended December 31, 2022 and 2021. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 (in millions of dollars) Accumulated Other Comprehensive Income (Loss) at Beginning of Year $ (383.2) $ (494.6) $ (34.0) $ (54.7) $ 21.2 $ 19.3 Net Actuarial Gain (Loss) Amortization 16.3 21.3 0.4 1.3 (1.0) — All Other Changes 87.7 124.8 (41.2) 26.3 19.0 2.6 Prior Service Credit (Cost) Amortization — — — — (0.2) (0.2) Change in Income Tax (25.7) (34.7) 10.4 (6.9) (3.8) (0.5) Accumulated Other Comprehensive Income (Loss) at End of Year $ (304.9) $ (383.2) $ (64.4) $ (34.0) $ 35.2 $ 21.2
Schedule of Assumptions Used	We use a December 31 measurement date for each of our plans. The weighted average assumptions used in the measurement of our benefit obligations as of December 31 and our net periodic benefit costs for the years ended December 31 are as follows: Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2022 2021 2022 2021 Benefit Obligations Discount Rate 5.70 % 3.10 % 4.80 % 2.00 % 5.70 % 2.90 % Rate of Compensation Increase N/A N/A 2.50 % 2.90 % N/A N/A Net Periodic Benefit Cost Discount Rate 3.10 % 2.90 % 2.00 % 1.40 % 2.90 % 2.60 % Expected Return on Plan Assets 6.00 % 6.00 % 4.20 % 3.50 % 5.75 % 5.75 % Rate of Compensation Increase N/A N/A 2.90 % 2.80 % N/A N/A
Schedule of Net Benefit Costs	Net Periodic Benefit Cost The following table provides the components of the net periodic benefit cost (credit) for the years ended December 31. Pension Benefits U.S. Plans U.K. Plan OPEB 2022 2021 2020 2022 2021 2020 2022 2021 2020 (in millions of dollars) Service Cost $ 7.7 $ 9.6 $ 11.0 $ — $ — $ — $ — $ — $ — Interest Cost 67.2 65.0 73.0 5.0 4.2 4.9 3.0 3.0 4.1 Expected Return on Plan Assets (105.9) (100.6) (106.7) (10.9) (9.8) (9.5) (0.5) (0.5) (0.5) Amortization of: Net Actuarial Loss (Gain) 16.3 21.3 18.7 0.4 1.3 1.1 (1.0) — — Prior Service Cost (Credit) — — 0.1 — — — (0.2) (0.2) (0.2) Curtailment Gain — — — — — 0.1 — — — Total Net Periodic Benefit Cost (Credit) $ (14.7) $ (4.7) $ (3.9) $ (5.5) $ (4.3) $ (3.4) $ 1.3 $ 2.3 $ 3.4
Schedule of Expected Benefit Payments	The following table provides expected benefit payments, which reflect expected future service, as appropriate. Pension Benefits U.S. Plans U.K. Plan OPEB (in millions of dollars) Year Gross Subsidy Payments Net 2023 $ 84.9 $ 5.4 $ 10.0 $ 0.1 $ 9.9 2024 88.2 5.5 9.4 0.1 9.3 2025 92.1 5.7 9.0 0.1 8.9 2026 96.5 5.8 8.5 — 8.5 2027 100.6 6.0 8.1 — 8.1 2028-2032 550.6 32.4 34.0 0.1 33.9
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Category	The categorization of fair value measurements by input level for the invested assets in our U.S. pension plans is shown below. The carrying values of investment-related receivables and payables approximate fair value due to the short-term nature of the securities and are not included in the following chart. Investments valued using net asset value (NAV) as a practical expedient are not required to be categorized by input level, but these investments are included as follows to reconcile to total invested assets. Certain prior year amounts were reclassified to conform to current year presentation. December 31, 2022 Quoted Prices Significant Other Significant NAV as a Practical Total (in millions of dollars) Invested Assets Equity Securities: Global $ 57.4 $ — $ — $ 405.7 $ 463.1 Fixed Income Securities: U.S. Government and Agencies 1 194.0 21.7 — — 215.7 Corporate — — — 129.6 129.6 Non-U.S. Emerging Markets — — — 54.0 54.0 Opportunistic Credits — — — 132.3 132.3 Real Estate — — — 164.2 164.2 Alternative Investments: Private Equity Direct Investments — — — 74.5 74.5 Private Equity Funds of Funds — — — 47.6 47.6 Cash Equivalents 20.5 — — — 20.5 Total Invested Assets $ 271.9 $ 21.7 $ — $ 1,007.9 $ 1,301.5 1 U.S. Government and Agencies Fixed Income Securities includes derivative assets. December 31, 2021 Quoted Prices Significant Significant NAV as a Practical Total (in millions of dollars) Invested Assets Equity Securities: U.S. Large Cap $ — $ — $ — $ 144.9 $ 144.9 U.S. Small Cap 32.8 — — 30.5 63.3 Global — — — 388.7 388.7 Emerging Markets — — — 59.8 59.8 Fixed Income Securities: U.S. Government and Agencies 1 419.3 — — — 419.3 Corporate — — — 103.3 103.3 Opportunistic Credits — — — 212.5 212.5 Real Estate — — — 247.1 247.1 Alternative Investments: Private Equity Direct Investments — — — 80.4 80.4 Private Equity Funds of Funds — — — 50.5 50.5 Cash Equivalents 31.9 — — — 31.9 Total Invested Assets $ 484.0 $ — $ — $ 1,317.7 $ 1,801.7 1 U.S. Government and Agencies Fixed Income Securities includes derivative assets.
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Category	The categorization of fair value measurements by input level for the invested assets in our U.K. pension plan is shown below. Investments valued using NAV as a practical expedient are not required to be categorized by input level, but these investments are included as follows to reconcile to total invested assets. December 31, 2022 Quoted Prices Significant Significant NAV as a Practical Total (in millions of dollars) Invested Assets Diversified Growth Assets $ 32.3 $ — $ — $ 8.3 $ 40.6 Fixed Income and Index-linked Securities 70.6 — — — 70.6 Alternative Investments — — — 28.1 28.1 Cash Equivalents 1.9 — — — 1.9 Total Invested Assets $ 104.8 $ — $ — $ 36.4 $ 141.2 December 31, 2021 Quoted Prices Significant Significant NAV as a Practical Total (in millions of dollars) Invested Assets Diversified Growth Assets $ 113.1 $ — $ — $ 44.2 $ 157.3 Fixed Income and Index-linked Securities 124.1 — — — 124.1 Alternative Investments — — — 18.2 18.2 Cash Equivalents 4.1 — — — 4.1 Total Invested Assets $ 241.3 $ — $ — $ 62.4 $ 303.7
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Category	The categorization of fair value measurements by input level for the assets in our OPEB plan is as follows: December 31, 2022 Quoted Prices Significant Other Significant Total (in millions of dollars) Assets Life Insurance Contracts $ — $ — $ 8.5 $ 8.5 December 31, 2021 Quoted Prices Significant Other Significant Total (in millions of dollars) Assets Life Insurance Contracts $ — $ — $ 9.0 $ 9.0
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets	Changes in our OPEB plan assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended December 31, 2022 and 2021 are as follows: Year Ended December 31, 2022 Beginning Actual Return on Plan Assets Contributions Net Benefits and Expenses Paid End of Year (in millions of dollars) Life Insurance Contracts $ 9.0 $ 0.1 $ 9.5 $ (10.1) $ 8.5 Year Ended December 31, 2021 Beginning Actual Return on Plan Assets Contributions Net Benefits and Expenses Paid End of Year (in millions of dollars) Life Insurance Contracts $ 9.3 $ 0.1 $ 9.9 $ (10.3) $ 9.0

Stockholders' Equity and Earn_2

Stockholders' Equity and Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity and Earnings Per Common Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	Net income per common share is determined as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars, except share data) Numerator Net Income $ 1,314.2 $ 824.2 $ 793.0 Denominator (000s) Weighted Average Common Shares - Basic 200,647.2 204,232.9 203,642.0 Dilution for Assumed Exercises of Stock Options and Nonvested Stock Awards 1,462.2 615.0 113.3 Weighted Average Common Shares - Assuming Dilution 202,109.4 204,847.9 203,755.3 Net Income Per Common Share Basic $ 6.55 $ 4.04 $ 3.89 Assuming Dilution $ 6.50 $ 4.02 $ 3.89
Treasury Stock Transactions	Common stock repurchases, which are accounted for using the cost method and classified as treasury stock until otherwise retired, were as follows: Year Ended December 31 2022 2021 2020 (in millions) Shares Repurchased 5.7 1.9 — Cost of Shares Repurchased 1 $ 200.1 $ 50.0 $ — 1 Includes commissions of $0.1 million for the year ended December 31, 2022.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award
Schedule of Compensation Cost for Share-based Payment Arrangements	Compensation expense for the stock based plans, as reported in our consolidated statements of income, is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Performance Share Units $ 5.7 $ 3.3 $ 5.6 Cash Incentive Units 12.8 3.2 — Restricted Stock Units and Cash-Settled Restricted Stock Units 32.7 25.5 23.9 Stock Success Units 0.9 2.8 0.4 Other 0.6 0.6 0.5 Total Compensation Expense, Before Income Tax $ 52.7 $ 35.4 $ 30.4 Total Compensation Expense, Net of Income Tax $ 47.3 $ 31.1 $ 26.1
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Valuation Assumptions on PSU Grants	The fair value of PSUs is estimated on the date of initial grant using the Monte-Carlo simulation m odel. Key assumptions used to value PSUs granted during 2020 are as follows: Year Ended December 31, 2020 Expected Volatility (based on our and our peer group historical daily stock prices) 23 % Expected Life (equals the performance period) 3 years Risk Free Interest Rate (based on U.S. Treasury yields at the date of grant) 0.85 %
Cash Incentive Units (CIUs)
Share-based Compensation Arrangement by Share-based Payment Award
Activity for CIUs	Activity for CIUs classified as a liability is as follows: Weighted Average Units Grant Date (000s) Fair Value Outstanding at December 31, 2021 7,223 $ 1.07 Granted 8,024 1.09 Outstanding at December 31, 2022 15,247 1.08
Schedule of Cash-based Payment Award, Cash-incentive Units, Valuation Assumptions	The fair value of CIUs is estimated at each reporting period using the Monte-Carlo simulation m odel. Key assumptions used to value CIUs granted during current year are as follows: Year Ended December 31 2022 2021 Expected Volatility (based on our and our peer group historical daily stock prices) 30 % 50 % Expected Life (equals the performance period) 3 years 3 years Risk Free Interest Rate (based on U.S. Treasury yields at the date of grant) 4.26 % 0.71 %
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Activity for Restricted Stock Units	Activity for RSUs classified as equity is as follows: Weighted Average Shares Grant Date (000s) Fair Value Outstanding at December 31, 2021 2,016 $ 26.63 Granted 1,323 28.21 Vested (1,018) 27.51 Forfeited (139) 26.19 Outstanding at December 31, 2022 2,182 27.20
Cash Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Payment Arrangement, Cash-Settled Restricted Stock Units, Activity	Activity for cash-settled RSUs classified as a liability is as follows: Weighted Average Shares Grant Date (000s) Fair Value Outstanding at December 31, 2021 46 $ 23.31 Vested (23) 23.31 Outstanding at December 31, 2022 23 23.31

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2022
Reinsurance Disclosures [Abstract]
Effects of Reinsurance	Reinsurance activity related to both our premium income and changes in reserves for future benefits are as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Direct Premium Income $ 9,900.5 $ 9,742.8 $ 9,621.9 Reinsurance Assumed 78.7 90.6 94.1 Reinsurance Ceded (355.8) (352.4) (337.9) Net Premium Income $ 9,623.4 $ 9,481.0 $ 9,378.1 Ceded Benefits and Change in Reserves for Future Benefits $ 1,034.6 $ 862.5 $ 628.8

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2022
Segment Reporting [Abstract]
Premium Income by Major Line of Business within Each Segment	Segment information is shown below. Certain prior year amounts were reclassified to conform to current year presentation. Year Ended December 31 2022 2021 2020 (in millions of dollars) Premium Income Unum US Group Disability Group Long-term Disability $ 1,911.7 $ 1,827.8 $ 1,828.5 Group Short-term Disability 926.3 864.0 799.2 Group Life and Accidental Death & Dismemberment Group Life 1,669.1 1,641.9 1,640.5 Accidental Death & Dismemberment 173.7 165.1 163.9 Supplemental and Voluntary Voluntary Benefits 840.6 846.7 875.2 Individual Disability 461.1 459.8 456.0 Dental and Vision 275.8 272.7 255.6 6,258.3 6,078.0 6,018.9 Unum International Unum UK Group Long-term Disability 376.9 401.9 364.9 Group Life 138.2 112.3 108.5 Supplemental 114.0 112.6 99.8 Unum Poland 89.7 90.2 79.6 718.8 717.0 652.8 Colonial Life Accident, Sickness, and Disability 948.9 953.3 975.1 Life 401.1 384.7 376.4 Cancer and Critical Illness 352.0 352.2 360.5 1,702.0 1,690.2 1,712.0 Closed Block Long-term Care 697.4 704.3 666.9 All Other 246.9 291.5 327.5 944.3 995.8 994.4 Total Premium Income $ 9,623.4 $ 9,481.0 $ 9,378.1
Selected Operating Statement Data by Segment	Unum US Unum International Colonial Life Closed Block Corporate Total (in millions of dollars) Year Ended December 31, 2022 Premium Income $ 6,258.3 $ 718.8 $ 1,702.0 $ 944.3 $ — $ 9,623.4 Net Investment Income 676.3 170.1 152.7 1,070.6 52.5 2,122.2 Other Income 196.3 0.9 1.1 58.0 4.8 261.1 Adjusted Operating Revenue $ 7,130.9 $ 889.8 $ 1,855.8 $ 2,072.9 $ 57.3 $ 12,006.7 Adjusted Operating Income (Loss) $ 970.7 $ 127.0 $ 374.6 $ 247.9 $ (164.3) $ 1,555.9 Interest and Debt Expense $ — $ — $ — $ — $ 192.7 $ 192.7 Depreciation and Amortization $ 370.6 $ 22.0 $ 303.5 $ 4.7 $ 0.6 $ 701.4 Year Ended December 31, 2021 Premium Income $ 6,078.0 $ 717.0 $ 1,690.2 $ 995.8 $ — $ 9,481.0 Net Investment Income 721.6 132.7 172.0 1,159.0 27.9 2,213.2 Other Income 170.0 0.6 1.0 65.1 6.2 242.9 Adjusted Operating Revenue $ 6,969.6 $ 850.3 $ 1,863.2 $ 2,219.9 $ 34.1 $ 11,937.1 Adjusted Operating Income (Loss) $ 464.9 $ 105.7 $ 329.2 $ 394.7 $ (177.9) $ 1,116.6 Interest and Debt Expense $ — $ — $ — $ — $ 185.0 $ 185.0 Depreciation and Amortization $ 400.9 $ 21.0 $ 275.4 $ 5.1 $ 0.7 $ 703.1 Year Ended December 31, 2020 Premium Income $ 6,018.9 $ 652.8 $ 1,712.0 $ 994.4 $ — $ 9,378.1 Net Investment Income 720.3 104.6 155.7 1,370.3 9.8 2,360.7 Other Income 154.9 0.5 1.1 66.6 1.1 224.2 Adjusted Operating Revenue $ 6,894.1 $ 757.9 $ 1,868.8 $ 2,431.3 $ 10.9 $ 11,963.0 Adjusted Operating Income (Loss) $ 825.4 $ 76.6 $ 335.4 $ 241.4 $ (200.8) $ 1,278.0 Interest and Debt Expense $ — $ — $ — $ 3.1 $ 185.1 $ 188.2 Depreciation and Amortization $ 421.7 $ 20.1 $ 273.9 $ 5.9 $ 0.7 $ 722.3
Deferred Policy Acquisition Costs by Segment	Unum Colonial Unum US International Life Total (in millions of dollars) Deferred Acquisition Costs Year Ended December 31, 2022 Beginning of Year $ 1,096.2 $ 35.4 $ 1,076.3 $ 2,207.9 Capitalization 273.1 12.0 271.8 556.9 Amortization (294.9) (7.6) (288.5) (591.0) Adjustment Related to Unrealized Investment Gains and Losses 15.0 — 66.7 81.7 Foreign Currency — (3.2) — (3.2) End of Year $ 1,089.4 $ 36.6 $ 1,126.3 $ 2,252.3 Year Ended December 31, 2021 Beginning of Year $ 1,168.7 $ 32.0 $ 1,071.9 $ 2,272.6 Capitalization 242.7 12.8 252.6 508.1 Amortization (319.0) (8.0) (259.1) (586.1) Adjustment Related to Unrealized Investment Gains and Losses 3.8 — 10.9 14.7 Foreign Currency — (1.4) — (1.4) End of Year $ 1,096.2 $ 35.4 $ 1,076.3 $ 2,207.9 Year Ended December 31, 2020 Beginning of Year $ 1,223.0 $ 26.4 $ 1,074.6 $ 2,324.0 Capitalization 291.5 12.1 272.6 576.2 Amortization (341.0) (7.4) (257.7) (606.1) Adjustment Related to Unrealized Investment Gains and Losses (4.8) — (17.6) (22.4) Foreign Currency — 0.9 — 0.9 End of Year $ 1,168.7 $ 32.0 $ 1,071.9 $ 2,272.6
Assets by Segment	December 31 2022 2021 (in millions of dollars) Assets Unum US $ 16,278.7 $ 18,696.3 Unum International 3,154.9 4,086.5 Colonial Life 4,448.9 4,895.9 Closed Block 34,241.2 38,287.9 Corporate 3,311.2 4,149.0 Total Assets $ 61,434.9 $ 70,115.6
Reconciliation of Total Revenue and Income Before Income Tax to Adjusted Operating Revenue and Adjusted Operating Income	A reconciliation of total revenue to "adjusted operating revenue" and income before income tax to "adjusted operating income" is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Total Revenue $ 11,991.0 $ 12,013.8 $ 13,162.1 Excluding: Net Investment Gain (Loss) (15.7) 76.7 1,199.1 Adjusted Operating Revenue $ 12,006.7 $ 11,937.1 $ 11,963.0 Income Before Income Tax $ 1,631.4 $ 1,063.0 $ 964.0 Excluding: Net Investment Gains and Losses Net Realized Investment Gain Related to Reinsurance Transaction — 67.6 1,302.3 Net Investment Gain (Loss), Other (15.7) 9.1 (103.2) Total Net Investment Gain (Loss) (15.7) 76.7 1,199.1 Items Related to Closed Block Individual Disability Reinsurance Transaction Change in Benefit Reserves and Transaction Costs — (139.3) (1,305.5) Amortization of the Cost of Reinsurance (63.8) (79.1) (2.6) Total Items Related to Closed Block Individual Disability Reinsurance Transaction (63.8) (218.4) (1,308.1) Net Reserve Change Related to Reserve Assumption Updates 155.0 181.4 (169.0) Impairment Loss on Internal-Use Software — (12.1) — Cost Related to Early Retirement of Debt — (67.3) — Impairment Loss on ROU Asset — (13.9) (12.7) Costs Related to Organizational Design Update — — (23.3) Adjusted Operating Income $ 1,555.9 $ 1,116.6 $ 1,278.0

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Lease, Cost	Operating lease information is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Lease Cost Operating Lease Cost $ 19.6 $ 35.2 $ 48.6 Sublease Income (1.1) (1.0) (1.3) Total Lease Cost $ 18.5 $ 34.2 $ 47.3 Other Information Cash Paid for Amounts Included in the Measurement of Lease Liabilities $ 23.1 $ 29.9 $ 30.8 Weighted-Average Remaining Lease Term 6 years 6 years 6 years Weighted-Average Discount Rate 4.32 % 4.45 % 4.37 %
Lessee, Operating Lease, Liability, Maturity	As of December 31, 2022, aggregate undiscounted minimum lease payments and the reconciliation to our lease liability are as follows (in millions of dollars): 2023 $ 18.2 2024 14.4 2025 11.1 2026 9.1 2027 8.3 2028 and Thereafter 17.4 Total 78.5 Less Imputed Interest 10.6 Lease Liability $ 67.9

Statutory Financial Informati_2

Statutory Financial Information (Tables)	12 Months Ended
	Dec. 31, 2022
Statutory Financial Information [Abstract]
Statutory Permitted Practices Disclosure	Additional information regarding the Unum America premium deficiency reserve (PDR) is as follows: Year Ended December 31 2022 2021 2020 (in millions of dollars) Premium Deficiency Reserve Gross Premium Deficiency Reserve 1 $ 2,851.0 $ 2,977.0 $ 2,290.0 Cumulative Gross Premium Deficiency Reserve Recognized 1,191.0 667.0 229.0 Remaining Premium Deficiency Reserve to be Recognized $ 1,660.0 $ 2,310.0 $ 2,061.0 1 The gross PDR decreased by $126.0 million due primarily to premium rate increase activity and underlying growth in the locked-in statutory reserve basis during 2022. The gross PDR increased by $687.0 million and $190.0 million during 2021 and 2020, respectively, due primarily to changes in the assumed reinvestment rate. The increase for 2020 was from the original $2,100.0 million reserve deficiency as of December 31, 2018.
Statutory Earnings and Surplus	The operating results and capital and surplus of our traditional U.S. life insurance subsidiaries and our captive reinsurers, prepared in accordance with prescribed or permitted accounting practices of the NAIC or states of domicile, are presented separately below. Year Ended December 31 2022 2021 2020 (in millions of dollars) Combined Net Income (Loss) Traditional U.S. Life Insurance Subsidiaries $ 965.4 $ 779.5 $ 646.8 Captive Reinsurers $ (432.2) $ (159.0) $ (201.0) Combined Net Gain (Loss) from Operations, After Tax Traditional U.S. Life Insurance Subsidiaries $ 965.4 $ 681.1 $ 726.2 Captive Reinsurers $ (428.6) $ (247.4) $ (149.4) December 31 2022 2021 (in millions of dollars) Combined Capital and Surplus Traditional U.S. Life Insurance Subsidiaries $ 3,816.3 $ 3,950.3 Captive Reinsurers $ 1,229.6 $ 1,258.4

Schedule II Condensed Financial

Schedule II Condensed Financial Information of Registrant (Tables) - Parent Company	12 Months Ended
	Dec. 31, 2022
Condensed Financial Statements, Captions
Condensed Financial Information of Parent Company Only Balance Sheets	BALANCE SHEETS December 31 2022 2021 (in millions of dollars) Assets Fixed Maturity Securities - at fair value (amortized cost: $748.1; $826.4) $ 657.7 $ 820.8 Other Long-term Investments 19.3 10.3 Short-term Investments 845.8 629.5 Investment in Subsidiaries 11,278.2 13,711.1 Deferred Income Tax 114.9 144.5 Other Assets 555.5 508.1 Total Assets $ 13,471.4 $ 15,824.3 Liabilities and Stockholders' Equity Liabilities Short-term Debt $ 2.0 $ — Long-term Debt 3,427.8 3,442.2 Pension and Postretirement Benefits 352.6 507.1 Other Liabilities 491.5 458.6 Total Liabilities 4,273.9 4,407.9 Stockholders' Equity Common Stock, $0.10 par Authorized: 725,000,000 shares Issued: 308,306,490 and 307,334,853 shares 30.8 30.7 Additional Paid-in Capital 2,441.0 2,408.1 Accumulated Other Comprehensive Income (Loss) (2,756.6) 354.1 Retained Earnings 12,912.1 11,853.2 Treasury Stock - at cost: 110,551,977 and 104,820,670 shares (3,429.8) (3,229.7) Total Stockholders' Equity 9,197.5 11,416.4 Total Liabilities and Stockholders' Equity $ 13,471.4 $ 15,824.3
Condensed Financial Information of Parent Company Only Statement of Earnings	STATEMENTS OF OPERATIONS Year Ended December 31 2022 2021 2020 (in millions of dollars) Cash Dividends from Subsidiaries $ 1,306.6 $ 909.8 $ 974.6 Non-Cash Dividends from Subsidiaries 23.0 719.6 — Other Income 81.8 53.5 51.7 Total Revenue 1,411.4 1,682.9 1,026.3 Interest and Debt Expense 188.5 185.9 187.1 Cost Related to Early Retirement of Debt 4.2 67.3 — Other Expenses 35.6 39.1 51.1 Total Expenses 228.3 292.3 238.2 Income of Parent Company Before Income Tax 1,183.1 1,390.6 788.1 Income Tax Expense (Benefit) 14.7 (24.1) (15.3) Income of Parent Company 1,168.4 1,414.7 803.4 Equity in Undistributed Earnings (Loss) of Subsidiaries 145.8 (590.5) (10.4) Net Income 1,314.2 824.2 793.0 Other Comprehensive Income (Loss), Net of Tax (3,110.7) (20.1) 336.9 Comprehensive Income (Loss) $ (1,796.5) $ 804.1 $ 1,129.9
Condensed Financial Information of Parent Company Only Statements of Cash Flows	STATEMENTS OF CASH FLOWS Year Ended December 31 2022 2021 2020 (in millions of dollars) Cash Provided by Operating Activities $ 1,250.2 $ 861.0 $ 964.0 Cash Flows from Investing Activities Proceeds from Sales and Maturities of Fixed Maturity Securities 192.1 245.5 138.8 Proceeds from Sales and Maturities of Other Investments 7.4 20.1 46.6 Purchase of Fixed Maturity Securities (102.7) (2.0) (384.7) Purchase of Other Investments (32.0) (0.9) (22.0) Net Sales (Purchases) of Short-term Investments (209.6) (465.0) 440.6 Cash Distributions to Subsidiaries (540.2) (300.9) (965.5) Net Purchases of Property and Equipment (94.0) (91.3) (81.6) Cash Used by Investing Activities (779.0) (594.5) (827.8) Cash Flows from Financing Activities Short-term Debt Repayment — — (400.0) Issuance of Long-term Debt 349.2 588.1 494.1 Long-term Debt Repayment (364.0) (500.0) — Cost Related to Early Retirement of Debt (3.6) (62.8) — Issuance of Common Stock 4.0 3.4 4.4 Repurchase of Common Stock (200.1) (50.0) — Dividends Paid to Stockholders (254.2) (239.4) (231.9) Other, Net 0.7 (1.6) (1.4) Cash Used by Financing Activities (468.0) (262.3) (134.8) Increase in Cash $ 3.2 $ 4.2 $ 1.4

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($) Integer $ / shares	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares	Jan. 01, 2021 USD ($)
New Accounting Pronouncements or Change in Accounting Principle
Number of Operating Segments | Integer	3
Premium Income	$ 9,623,400,000	$ 9,481,000,000	$ 9,378,100,000
Commissions	1,086,400,000	1,038,100,000	1,057,300,000
Ceded Policy Loans	3,312,500,000	3,373,700,000
Premium Receivable, Allowance for Credit Loss	32,500,000	34,200,000
Premiums Receivable, Gross	557,600,000	530,700,000
Premium Receivable, Credit Loss Expense (Reversal)	(1,700,000)	(4,600,000)
Accumulated Depreciation for Property and Equipment	1,328,700,000	1,259,600,000
Value of Business Acquired	62,900,000	73,100,000
Accumulated Amortization of Value of Business Acquired	150,300,000	157,700,000
Amortization of Value of Business Acquired	4,900,000	5,700,000	6,100,000
Prepaid Reinsurance Premiums	713,300,000	777,100,000
Deferred Gain on Reinsurance	3,100,000	3,700,000
Reinsurance Recoverable, Allowance for Credit Loss	1,700,000	2,300,000
Reinsurance Recoverable, Credit Loss Expense (Reversal)	(600,000)	(9,400,000)
Premium Tax Expense	169,300,000	166,000,000	175,500,000
Participation Fund Account Assets (PFA)	250,200,000	297,700,000
Net Income	$ 1,314,200,000	$ 824,200,000	$ 793,000,000
Diluted Earnings Per Share | $ / shares	$ 6.50	$ 4.02	$ 3.89
Accumulated Other Comprehensive Income (Loss)	$ (2,756,600,000)	$ 354,100,000
Basic Earnings Per Share | $ / shares	$ 6.55	$ 4.04	$ 3.89
Pro Forma | Accounting Standards Update 2018-12 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle
Accumulated Other Comprehensive Income (Loss)				$ 6,700,000,000
Minimum | Pro Forma | Accounting Standards Update 2018-12 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle
Net Income	$ 80,000,000	$ 145,000,000
Diluted Earnings Per Share | $ / shares	$ 0.40	$ 0.70
Accumulated Other Comprehensive Income (Loss)	$ 600,000,000	$ 5,400,000,000
Maximum | Pro Forma | Accounting Standards Update 2018-12 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle
Net Income	$ 110,000,000	$ 175,000,000
Diluted Earnings Per Share | $ / shares	$ 0.55	$ 0.85
Accumulated Other Comprehensive Income (Loss)	$ 800,000,000	$ 5,600,000,000
Change in Accounting Method Accounted for as Change in Estimate
New Accounting Pronouncements or Change in Accounting Principle
Premium Income	(13,400,000)
Commissions	(1,000,000)
Net Income	$ (9,800,000)
Diluted Earnings Per Share | $ / shares	$ 0.05
Basic Earnings Per Share | $ / shares	$ 0.05

Fair Values of Financial Inst_3

Fair Values of Financial Instruments Private Equity Partnerships (Details) - Private Equity Partnerships - USD ($) $ in Millions		Dec. 31, 2022	Dec. 31, 2021
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		$ 1,194.3	$ 978.6
Alternative Investments, Unfunded Commitments		776.9	753.2
Private Credit
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		275	279.4
Alternative Investments, Unfunded Commitments		104.3	150.5
Private Credit | Not Redeemable
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments	[1]	239.3	240.6
Alternative Investments, Unfunded Commitments		90.9	143.7
Private Credit | Initial 2 year lock on each new investment / Quarterly after 2 year lock with 90 days notice
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		35.7	38.8
Alternative Investments, Unfunded Commitments		13.4	6.8
Private Equity Limited Partnership
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		485.3	384.6
Alternative Investments, Unfunded Commitments		416.3	324.6
Private Equity Limited Partnership | Not Redeemable
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments	[2]	453.6	365.8
Alternative Investments, Unfunded Commitments		377.2	274.3
Private Equity Limited Partnership | Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		31.7	18.8
Alternative Investments, Unfunded Commitments		39.1	50.3
Real Assets
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		434	314.6
Alternative Investments, Unfunded Commitments		256.3	278.1
Real Assets | Not Redeemable
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments	[3]	373.9	256.2
Alternative Investments, Unfunded Commitments		256.3	278.1
Real Assets | Quarterly / 90 days notice
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Alternative Investments		60.1	58.4
Alternative Investments, Unfunded Commitments		$ 0	$ 0
[1] Private Credit - The limited partnerships described in this category employ various investment strategies, generally providing direct lending or other forms of debt financing including first-lien, second-lien, mezzanine, and subordinated loans. The limited partnerships have credit exposure to corporates, physical assets, and/or financial assets within a variety of industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail) in North America and, to a lesser extent, outside of North America. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 55 percent in the next 3 years, 34 percent during the period from 3 to 5 years, 9 percent during the period from 5 to 10 years, and 2 percent during the period from 10 to 15 years. Private Equity - The limited partnerships described in this category employ various strategies generally investing in controlling or minority control equity positions directly in companies and/or assets across various industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail), primarily in private markets within North America and, to a lesser extent, outside of North America. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 35 percent in the next 3 years, 19 percent during the period from 3 to 5 years, 40 percent during the period from 5 to 10 years, and 6 percent during the period from 10 to 15 years. Real Assets - The limited partnerships described in this category employ various strategies, which include investing in the equity and/or debt financing of physical assets, including infrastructure (energy, power, water/wastewater, communications), transportation (including airports, ports, toll roads, aircraft, railcars) and real estate in North America, Europe, South America, and Asia. As of December 31, 2022, the estimated remaining life of the investments that do not allow for redemptions is approximately 22 percent in the next 3 years, 28 percent during period from 3 to 5 years and 50 percent during the period from 5 to 10 years.

Fair Value Measurements by Inpu

Fair Value Measurements by Input Level (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets
Fixed Maturity Securities	$ 34,840.8	$ 43,336
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets	$ 89.1	39.5
Equity Securities	25.8	33.7
Other Long-term Investments	1,440.1	1,203
Assets, Fair Value Disclosure	$ 36,150	44,387.8
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		65.1
Liabilities, Fair Value Disclosure	$ 87.9	65.1
Forwards
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Foreign Exchange Contracts
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		35
Embedded Derivative in Modified Coinsurance Arrangement
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		30.1
Fair Value, Measurements, Recurring
Assets
Other Long-term Investments	$ 1,309.2	1,051.8
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	$ 4,519.1	3,519.5
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		0
Equity Securities	$ 0	0
Other Long-term Investments	0	0
Assets, Fair Value Disclosure	4,519.1	3,519.5
Liabilities
Liabilities, Fair Value Disclosure	$ 0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Forwards
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Foreign Exchange Contracts
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Embedded Derivative in Modified Coinsurance Arrangement
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	$ 30,140.8	38,689.1
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		39.5
Equity Securities	$ 9.6	27.9
Other Long-term Investments	98.7	67.4
Assets, Fair Value Disclosure	30,239.5	38,756.5
Liabilities
Liabilities, Fair Value Disclosure	$ 74	35
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Forwards
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Foreign Exchange Contracts
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		35
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Embedded Derivative in Modified Coinsurance Arrangement
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	$ 180.9	1,127.4
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		0
Equity Securities	$ 16.2	5.8
Other Long-term Investments	16.2	5.8
Assets, Fair Value Disclosure	197.1	1,133.2
Liabilities
Liabilities, Fair Value Disclosure	$ 13.9	30.1
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Forwards
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Foreign Exchange Contracts
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Embedded Derivative in Modified Coinsurance Arrangement
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		30.1
Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	$ 0	0
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		0
Equity Securities	$ 0	0
Other Long-term Investments	1,194.3	978.6
Assets, Fair Value Disclosure	1,194.3	978.6
Liabilities
Liabilities, Fair Value Disclosure	$ 0	0
Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share | Forwards
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share | Foreign Exchange Contracts
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		0
Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share | Embedded Derivative in Modified Coinsurance Arrangement
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		0
United States Government and Government Agencies and Authorities
Assets
Fixed Maturity Securities	$ 498.2	580.1
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	81.7	0
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	416.5	580.1
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	0	0
United States Government and Government Agencies and Authorities | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	0	0
States, Municipalities, and Political Subdivisions
Assets
Fixed Maturity Securities	3,457.2	4,727.5
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	8.7	0
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	3,448.3	4,714.1
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	0.2	13.4
States, Municipalities, and Political Subdivisions | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	0	0
Foreign Governments
Assets
Fixed Maturity Securities	827.1	1,146.6
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	0	0
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	827.1	1,125.8
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	0	20.8
Foreign Governments | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	0	0
Public Utilities
Assets
Fixed Maturity Securities	4,956.9	6,416
Public Utilities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	160.1	230.8
Public Utilities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	4,796.8	6,140.7
Public Utilities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	0	44.5
Public Utilities | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	0	0
Mortgage/Asset-backed Securities
Assets
Fixed Maturity Securities	573.3	638.3
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	0	0
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	551.3	451.1
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	22	187.2
Mortgage/Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	0	0
All Other Corporate Bonds
Assets
Fixed Maturity Securities	24,524.6	29,823.4
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	4,268.6	3,288.7
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	20,097.3	25,673.2
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	158.7	861.5
All Other Corporate Bonds | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	0	0
Redeemable Preferred Stocks
Assets
Fixed Maturity Securities	3.5	4.1
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Fixed Maturity Securities	0	0
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Fixed Maturity Securities	3.5	4.1
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Fixed Maturity Securities	0	0
Redeemable Preferred Stocks | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Fixed Maturity Securities	$ 0	0
Forwards
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Forwards | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Forwards | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Forwards | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Forwards | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Foreign Exchange Contracts
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		39.5
Foreign Exchange Contracts | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		0
Foreign Exchange Contracts | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		39.5
Foreign Exchange Contracts | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		0
Foreign Exchange Contracts | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-term Investments
Derivative Assets		0
Private Equity Partnerships
Assets
Alternative Investments	$ 1,194.3	978.6
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Alternative Investments	0	0
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Alternative Investments	0	0
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Alternative Investments	0	0
Private Equity Partnerships | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Alternative Investments	$ 1,194.3	978.6
Derivatives | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		0
Derivatives | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		35
Derivatives | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		30.1
Derivatives | Fair Value, Measurements, Recurring | Fair Value Measured at Net Asset Value Per Share
Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities
Liabilities
Derivative Liabilities		$ 0

Changes in Assets and Liabiliti

Changes in Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Unobservable Inputs (Level 3) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Embedded Derivative in Modified Coinsurance Arrangement
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Derivatives Measured with Unobservable Inputs, Beginning Balance	$ (30.1)	$ (39.8)
Derivative Liability Gain (Loss) Included in Earnings	16.2	9.7
Derivative Liability Gain (Loss) Included in OCI	0	0
Derivative Purchases	0	0
Derivative Sales	0	0
Derivative Transfers Into Level 3	0	0
Derivative Transfers Out of Level 3	0	0
Derivatives Measured with Unobservable Inputs, Ending Balance	(13.9)	(30.1)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0	0
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	16.2	9.7
States, Municipalities, and Political Subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Assets Measured with Unobservable Inputs, Beginning Balance	13.4	15.5
Investment Gain (Loss) included in Earnings	0	0
Investment Gain (Loss) included in OCI	(0.1)	(2.1)
Investment Purchases	0	0
Investment Sales	0	0
Investment Level 3 Transfers Into	0.3	0
Investment Level 3 Transfers Out of	13.4	0
Assets Measured with Unobservable Inputs, Ending Balance	0.2	13.4
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0.1	2.1
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0
Foreign Governments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Assets Measured with Unobservable Inputs, Beginning Balance	20.8	21.8
Investment Gain (Loss) included in Earnings	0	0
Investment Gain (Loss) included in OCI	(0.8)	(1)
Investment Purchases	0	0
Investment Sales	(20)	0
Investment Level 3 Transfers Into	0	0
Investment Level 3 Transfers Out of	0	0
Assets Measured with Unobservable Inputs, Ending Balance	0	20.8
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0.8	1
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0
Public Utilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Assets Measured with Unobservable Inputs, Beginning Balance	44.5	185.7
Investment Gain (Loss) included in Earnings	0	0
Investment Gain (Loss) included in OCI	(2.8)	(2.3)
Investment Purchases	0	0
Investment Sales	(12.8)	(44)
Investment Level 3 Transfers Into	15.6	36
Investment Level 3 Transfers Out of	44.5	130.9
Assets Measured with Unobservable Inputs, Ending Balance	0	44.5
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	2.8	2.3
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0
Mortgage/Asset-backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Assets Measured with Unobservable Inputs, Beginning Balance	187.2	81.3
Investment Gain (Loss) included in Earnings	0	0
Investment Gain (Loss) included in OCI	(0.3)	(96)
Investment Purchases	20.7	0
Investment Sales	(10.6)	(72.3)
Investment Level 3 Transfers Into	0	274.2
Investment Level 3 Transfers Out of	175	0
Assets Measured with Unobservable Inputs, Ending Balance	22	187.2
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0.3	96
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0
All Other Corporate Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Assets Measured with Unobservable Inputs, Beginning Balance	861.5	943.1
Investment Gain (Loss) included in Earnings	0	0
Investment Gain (Loss) included in OCI	(32)	(24.6)
Investment Purchases	25.3	249.9
Investment Sales	(102.3)	(80.2)
Investment Level 3 Transfers Into	161.9	77.6
Investment Level 3 Transfers Out of	755.7	304.3
Assets Measured with Unobservable Inputs, Ending Balance	158.7	861.5
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	32	24.6
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0
Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Assets Measured with Unobservable Inputs, Beginning Balance	1,127.4	1,247.4
Investment Gain (Loss) included in Earnings	0	0
Investment Gain (Loss) included in OCI	(36)	(126)
Investment Purchases	46	249.9
Investment Sales	(145.7)	(196.5)
Investment Level 3 Transfers Into	177.8	387.8
Investment Level 3 Transfers Out of	988.6	435.2
Assets Measured with Unobservable Inputs, Ending Balance	180.9	1,127.4
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	36	126
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	0	0
Perpetual Preferred Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Assets Measured with Unobservable Inputs, Beginning Balance	5.8	4.7
Investment Gain (Loss) included in Earnings	3	0.1
Investment Gain (Loss) included in OCI	0	0
Investment Purchases	7.1	1
Investment Sales	0	0
Investment Level 3 Transfers Into	0.3	0
Investment Level 3 Transfers Out of	0	0
Assets Measured with Unobservable Inputs, Ending Balance	16.2	5.8
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	$ 3	$ 0.1

Quantitative Information Regard

Quantitative Information Regarding Significant Unobservable Inputs (Details) $ in Millions		Dec. 31, 2022 USD ($) Rate	Dec. 31, 2021 USD ($) Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity Securities | $		$ 25.8	$ 33.7
Fair Value, Inputs, Level 3 | Discounted Cash Flow | Embedded Derivative in Modified Coinsurance Arrangement
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative in Modified Coinsurance Arrangement | $	[1]	$ (13.9)	$ (30.1)
Fair Value, Inputs, Level 3 | Discounted Cash Flow | Embedded Derivative in Modified Coinsurance Arrangement | Weighted Average | Input Measurement, Spread of Swap Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Liability, Measurement Input		0.006	0.007
Fair Value, Inputs, Level 3 | All Other Corporate Bonds | Market Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private | $	[2]	$ 15.3	$ 111.8	[3],[4]
Fair Value, Inputs, Level 3 | All Other Corporate Bonds | Market Approach | Minimum | Volatility of Credit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input		0.0541	0.0630
Fair Value, Inputs, Level 3 | All Other Corporate Bonds | Market Approach | Minimum | Lack of Marketability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input			0.0014
Fair Value, Inputs, Level 3 | All Other Corporate Bonds | Market Approach | Maximum | Volatility of Credit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input		0.0541	0.0630
Fair Value, Inputs, Level 3 | All Other Corporate Bonds | Market Approach | Maximum | Lack of Marketability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input			0.0073
Fair Value, Inputs, Level 3 | All Other Corporate Bonds | Market Approach | Weighted Average | Volatility of Credit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input		0.0541	0.0630
Fair Value, Inputs, Level 3 | All Other Corporate Bonds | Market Approach | Weighted Average | Lack of Marketability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
All Other Corporate Bonds - Private, Measurement Input			0.0051
Fair Value, Inputs, Level 3 | Perpetual Preferred Securities | Market Approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity Securities | $	[4]	$ 16.2	$ 5.8
[1] (d) Represents various actuarial assumptions required to derive the liability cash flows. Fair value of embedded derivative is most often driven by the change in the weighted average credit spread to the swap curve for the assets backing the hypothetical loan

Fair Values of Financial Inst_4

Fair Values of Financial Instruments Carrying Amounts and Estimated Fair value of Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans	$ 2,435.4	$ 2,560.4
Policy Loans	3,601.2	3,662.9
Long-term Debt	3,427.8	3,442.2
Unfunded Commitments	0.7
Liabilities, Fair Value Disclosure	87.9	65.1
Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	2,159.5	2,677.8
Mortgage Loans	2,435.4	2,560.4
Policy Loans, Fair Value Disclosure	3,677	3,807.1
Policy Loans	3,601.2	3,662.9
Miscellaneous Long-Term Investments, Fair Value Disclosure	18.4	31.6
Miscellaneous Long-Term Investments	18.4	31.6
Financial Instruments, Financial Assets Fair Value Disclosure	5,854.9	6,516.5
Total Financial Instrument Assets Not Carried at Fair Value	6,055	6,254.9
Long-term Debt, Fair Value Disclosure	3,072	3,879.1
Long-term Debt	3,427.8	3,442.2
Unfunded Commitments	0.7	0.7
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	99.1	160.9
Federal Home Loan Bank Funding Agreements	99.1	160.9
Liabilities, Fair Value Disclosure	3,171.8	4,040.7
Total Financial Instrument Liabilities Not Carried at Fair Value	3,527.6	3,603.8
Fair Value, Inputs, Level 1 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	0	0
Policy Loans, Fair Value Disclosure	0	0
Miscellaneous Long-Term Investments, Fair Value Disclosure	0	0
Financial Instruments, Financial Assets Fair Value Disclosure	0	0
Long-term Debt, Fair Value Disclosure	2,288.9	2,237.3
Unfunded Commitments	0	0
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	2,288.9	2,237.3
Fair Value, Inputs, Level 2 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	2,159.5	2,677.8
Policy Loans, Fair Value Disclosure	0	0
Miscellaneous Long-Term Investments, Fair Value Disclosure	17.1	22.1
Financial Instruments, Financial Assets Fair Value Disclosure	2,176.6	2,699.9
Long-term Debt, Fair Value Disclosure	783.1	1,641.8
Unfunded Commitments	0.7	0.7
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	99.1	160.9
Liabilities, Fair Value Disclosure	882.9	1,803.4
Fair Value, Inputs, Level 3 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Mortgage Loans, Fair Value Disclosure	0	0
Policy Loans, Fair Value Disclosure	3,677	3,807.1
Miscellaneous Long-Term Investments, Fair Value Disclosure	1.3	9.5
Financial Instruments, Financial Assets Fair Value Disclosure	3,678.3	3,816.6
Long-term Debt, Fair Value Disclosure	0	0
Unfunded Commitments	0	0
Federal Home Loan Bank Funding Agreements, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	$ 0	$ 0

Fair Value of Financial Instrum

Fair Value of Financial Instruments Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Ceded Policy Loans	$ 3,312.5	$ 3,373.7
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	13%
Fair Value, Inputs, Level 2 | Pricing Service
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	71%
Fair Value, Inputs, Level 2 | Other Observable Market Data
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	15.10%
Fair Value Inputs Other Than Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	87%
Fair Value Inputs Level 2 Or Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Percentage of Total Fair Value of Fixed Maturities Securities	0.90%

Amortized Cost and Fair Values

Amortized Cost and Fair Values of Securities by Security Type (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2020
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	$ 37,825.2	$ 37,386.7
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	743.6
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3,728
Debt Securities, Available-for-sale, Total	34,840.8	43,336
United States Government and Government Agencies and Authorities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	503.8	460.1
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	20.3	120.1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	25.9	0.1
Debt Securities, Available-for-sale, Total	498.2	580.1
States, Municipalities, and Political Subdivisions
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	4,006	4,150.2
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	87.1	584.2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	635.9	6.9
Debt Securities, Available-for-sale, Total	3,457.2	4,727.5
Foreign Governments
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	908.1	952
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	34.9	215.3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	115.9	20.7
Debt Securities, Available-for-sale, Total	827.1	1,146.6
Public Utilities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	5,170.9	5,266.4
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	141	1,159.4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	355	9.8
Debt Securities, Available-for-sale, Total	4,956.9	6,416
Mortgage/Asset-backed Securities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	592.1	587.9
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	8.2	50.4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	27	0
Debt Securities, Available-for-sale, Total	573.3	638.3
All Other Corporate Bonds
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	26,640.3	25,966.1
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	$ 6.8
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	452.1	3,919.9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2,567.8	62.6
Debt Securities, Available-for-sale, Total	24,524.6	29,823.4
Redeemable Preferred Stocks
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	4	4
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0.1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0.5	0
Debt Securities, Available-for-sale, Total	3.5	4.1
Fixed Maturity Securities
Debt Securities, Available-for-sale
Amortized Cost of Fixed Maturity Securities	37,825.2	37,386.7
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	743.6	6,049.4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3,728	100.1
Debt Securities, Available-for-sale, Total	$ 34,840.8	$ 43,336

Length of Time Fixed Maturity S

Length of Time Fixed Maturity Securities had been in a Gross Unrealized Loss Position (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
United States Government and Government Agencies and Authorities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 246.6	$ 9.3
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	22.6	0.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	12.2	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3.3	0
States, Municipalities, and Political Subdivisions
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,920.1	326.4
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	476.1	6.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	346.6	0.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	159.8	0
Foreign Governments
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	160.1	234.4
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	47.9	18.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	176.9	10.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	68	1.8
Public Utilities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,242.2	263.3
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	252	9.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	255.2	17.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	103	0.7
Mortgage/Asset-backed Securities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	386.6	29.2
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	27	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0.1	0.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
All Other Corporate Bonds
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	15,865.6	2,146.3
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,799.7	51.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,194.1	199.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	768.1	11
Redeemable Preferred Stocks
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3.5
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Fixed Maturity Securities
Debt Securities, Available-for-sale, Unrealized Loss Position
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	20,824.7	3,008.9
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,625.8	86.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,985.1	228.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1,102.2	$ 13.5

Investments Distribution of the

Investments Distribution of the Maturity Dates for Fixed Maturity Securities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale, Amortized Cost, Net of Allowance for Credit Losses, Fiscal Year Maturity [Abstract]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 1,133.5	$ 767.3
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five, Net	7,090.8	6,613.2
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10, Net	10,096.7	10,614.3
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10, Net	18,912.1	18,804
Available for sale Securities Debt Maturities Amortized Cost Gross Subtotal, Net	37,233.1	36,798.8
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost, Net	592.1	587.9
Debt Securities, Available-for-sale, Amortized Cost, Net of Allowance for Credit Losses	37,825.2	37,386.7
Available for Sale Securities Unrealized Gain Position Gross Gain [Abstract]
Available For Sale Securities Debt Maturities Within One Year Unrealized Gain Position Gross Gain	2.9	17.6
Available For Sale Securities Debt Maturities After One Through Five Years Unrealized Gain Position Gross Gain	86.7	540.2
Available For Sale Securities Debt Maturities After Five Through Ten Years Unrealized Gain Position Gross Gain	294.8	1,453.3
Available For Sale Securities Debt Maturities After Ten Years Unrealized Gain Position Gross Gain	351	3,987.9
Available For Sale Securities Debt Maturities Unrealized Gain Position Gross Gain Gross Subtotal	735.4	5,999
Available For Sale Securities Debt Maturities Without Single Maturity Date Unrealized Gain Position Gross Gain	8.2	50.4
Available for sale Securities, Debt Maturities Unrealized Gain Position Gross Gain	743.6	6,049.4
Available for Sale Securities Unrealized Loss Position Gross Loss [Abstract]
Available For Sale Securities Debt Maturities Within One Year Unrealized Loss Position Gross Loss	5.7	0.1
Available For Sale Securities Debt Maturities After One Through Five Years Unrealized Loss Position Gross Loss	238.4	6
Available For Sale Securities Debt Maturities After Five Through Ten Years Unrealized Loss Position Gross Loss	863.8	26
Available For Sale Securities Debt Maturities After Ten Years Unrealized Loss Position Gross Loss	2,593.1	68
Available For Sale Securities Debt Maturities Unrealized Gain Position Gross Loss Gross Subtotal	3,701	100.1
Available For Sale Securities Debt Maturities Without Single Maturity Date Unrealized Loss Position Gross Loss	27	0
Available For Sale Securities Unrealized Loss Position Gross Loss Subtotal	3,728	100.1
Fair Value Maturity Distribution [Abstract]
Debt Securities, Available-for-sale, Total	34,840.8	43,336
Available for Sale Securities Unrealized Gain Position Fair Value
Fair Value Maturity Distribution [Abstract]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	339.1	756
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	1,953.2	7,050.5
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	3,538.9	10,905
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	5,013.2	20,778.4
Available for sale Securities Debt Maturities Fair Value Gross Subtotal	10,844.4	39,489.9
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	186.6	609
Debt Securities, Available-for-sale, Total	11,031	40,098.9
Available for Sale Securities Unrealized Loss Position Fair Value
Fair Value Maturity Distribution [Abstract]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	791.6	28.9
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	4,985.9	96.9
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	5,988.8	1,136.6
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	11,656.8	1,945.4
Available for sale Securities Debt Maturities Fair Value Gross Subtotal	23,423.1	3,207.8
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	386.7	29.3
Debt Securities, Available-for-sale, Total	$ 23,809.8	$ 3,237.1

Investments Distribution by Ext

Investments Distribution by External Credit Rating for Fixed Maturity Securities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale
Fixed Maturity Securities	$ 34,840.8	$ 43,336
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	743.6
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 3,728
Fixed maturity securities in unrealized loss position percent of total	100%
External Credit Rating, Investment Grade
Debt Securities, Available-for-sale
Fixed Maturity Securities	$ 32,851
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	734.6
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 3,545.5
Fixed maturity securities in unrealized loss position percent of total	95.10%
External Credit Rating, Below-Investment-Grade
Debt Securities, Available-for-sale
Fixed Maturity Securities	$ 1,989.8
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 182.5
Fixed maturity securities in unrealized loss position percent of total	4.90%

Debt Securities, Available-for-

Debt Securities, Available-for-sale, Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2020
Debt Securities, Available-for-sale, Allowance for Credit Loss
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 0	$ 0
All Other Corporate Bonds
Debt Securities, Available-for-sale, Allowance for Credit Loss
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	$ 6.8
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded		0
Change in allowance due to change in intent to hold securities to maturity		0.5
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(7.3)
Public Utilities
Debt Securities, Available-for-sale, Allowance for Credit Loss
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	4.6
Change in allowance due to change in intent to hold securities to maturity	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	$ (4.6)

Investments Low Income Housing

Investments Low Income Housing Tax Credits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Low Income Housing Tax Credits [Abstract]
Affordable Housing Tax Credits	$ 8	$ 21.6	$ 33.2
Amortization of Affordable Housing Tax Credit Investments	(5.9)	(15)	(21.9)
Tax Benefits from Low Income Housing Investments	$ 2.1	$ 6.6	$ 11.3

Mortgage Loans by Property Type

Mortgage Loans by Property Type and Geographic Region (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Mortgage Loans on Real Estate
Mortgage Loans	$ 2,435.4	$ 2,560.4
Percent of Total	100%	100%
New England
Mortgage Loans on Real Estate
Mortgage Loans	$ 52.4	$ 54.9
Percent of Total	2.20%	2.10%
Mid-Atlantic
Mortgage Loans on Real Estate
Mortgage Loans	$ 192.4	$ 214.7
Percent of Total	7.90%	8.40%
East North Central
Mortgage Loans on Real Estate
Mortgage Loans	$ 313	$ 298.4
Percent of Total	12.90%	11.70%
West North Central
Mortgage Loans on Real Estate
Mortgage Loans	$ 181.4	$ 193.1
Percent of Total	7.40%	7.50%
South Atlantic
Mortgage Loans on Real Estate
Mortgage Loans	$ 539.3	$ 582.1
Percent of Total	22.10%	22.70%
East South Central
Mortgage Loans on Real Estate
Mortgage Loans	$ 101.8	$ 120.7
Percent of Total	4.20%	4.70%
West South Central
Mortgage Loans on Real Estate
Mortgage Loans	$ 212.6	$ 243.2
Percent of Total	8.70%	9.60%
Mountain
Mortgage Loans on Real Estate
Mortgage Loans	$ 298.7	$ 290.6
Percent of Total	12.30%	11.30%
Pacific
Mortgage Loans on Real Estate
Mortgage Loans	$ 543.8	$ 562.7
Percent of Total	22.30%	22%
Apartment
Mortgage Loans on Real Estate
Mortgage Loans	$ 688.6	$ 780
Percent of Total	28.30%	30.50%
Industrial
Mortgage Loans on Real Estate
Mortgage Loans	$ 745.3	$ 734.4
Percent of Total	30.60%	28.70%
Office
Mortgage Loans on Real Estate
Mortgage Loans	$ 423	$ 467.2
Percent of Total	17.40%	18.20%
Retail
Mortgage Loans on Real Estate
Mortgage Loans	$ 534.5	$ 533.3
Percent of Total	21.90%	20.80%
Other Property
Mortgage Loans on Real Estate
Mortgage Loans	$ 44	$ 45.5
Percent of Total	1.80%	1.80%

Schedule of Participating Mortg

Schedule of Participating Mortgage Loans by Internal Credit Rating and Loan to Value (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Mortgage Loans on Real Estate
Mortgage Loans	$ 2,435.4	$ 2,560.4
Percent of Total	100%	100%
Loan to Value Ratio Below or Equal to 65 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 1,389.6	$ 1,346.1
Percent of Total	57%	52.60%
Loan To Value Ratio Above 65 To 75 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 937.2	$ 1,076.8
Percent of Total	38.50%	42%
Loan To Value Ratio Above 75 To 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 75	$ 114.9
Percent of Total	3.10%	4.50%
Loan To Value Ratio Above 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 33.6	$ 22.6
Percent of Total	1.40%	0.90%
Total
Mortgage Loans on Real Estate
Percent of Total	100%	100%
AA Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 92.3	$ 27.3
Percent of Total	3.80%	1.10%
A Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 843.9	$ 709.6
Percent of Total	34.60%	27.70%
BBB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 1,458	$ 1,802.6
Percent of Total	59.90%	70.40%
BB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 41.2	$ 20.9
Percent of Total	1.70%	0.80%
Total
Mortgage Loans on Real Estate
Percent of Total	100%	100%

Mortgage Loans Sorted by Applic

Mortgage Loans Sorted by Applicable Credit Quality Indicators (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator
Financing Receivable, Allowance for Credit Loss	$ (9.3)
Mortgage Loans	2,435.4	$ 2,560.4
Loan to Value Ratio Below or Equal to 65 Percent
Financing Receivable, Credit Quality Indicator
Mortgage Loans	1,389.6	1,346.1
Loan To Value Ratio Above 65 To 75 Percent
Financing Receivable, Credit Quality Indicator
Mortgage Loans	937.2	1,076.8
Loan To Value Ratio Above 75 To 85 Percent
Financing Receivable, Credit Quality Indicator
Mortgage Loans	75	114.9
Loan To Value Ratio Above 85 Percent
Financing Receivable, Credit Quality Indicator
Mortgage Loans	33.6	22.6
Originated Five or More Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Mortgage Loans	1,104.2	981.5
Originated Four Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Mortgage Loans	374.7	304.1
Originated Three Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Mortgage Loans	343.5	383
Originated Two Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Mortgage Loans	169.3	359.4
Originated in Fiscal Year before Latest Fiscal Year
Financing Receivable, Credit Quality Indicator
Mortgage Loans	355.6	180
Originated in Current Fiscal Year
Financing Receivable, Credit Quality Indicator
Mortgage Loans	88.1	352.4
AA Credit Rating
Financing Receivable, Credit Quality Indicator
Mortgage Loans	92.3	27.3
A Credit Rating
Financing Receivable, Credit Quality Indicator
Mortgage Loans	843.9	709.6
BBB Credit Rating
Financing Receivable, Credit Quality Indicator
Mortgage Loans	1,458	1,802.6
BB Credit Rating
Financing Receivable, Credit Quality Indicator
Mortgage Loans	41.2	20.9
Commercial Real Estate
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,108.5	984.1
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	376.5	305.5
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	344.8	384.4
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	169.9	360.8
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	356.4	180.7
Financing Receivable, Year One, Originated, Current Fiscal Year	88.6	353.2
Financing Receivable, before Allowance for Credit Loss	2,444.7	2,568.7
Financing Receivable, Allowance for Credit Loss	(9.3)	(8.3)
Commercial Real Estate | Loan to Value Ratio Below or Equal to 65 Percent
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	782.6	779.1
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	189	146.9
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	193.9	163
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	81.3	80.7
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	128.9	54.3
Financing Receivable, Year One, Originated, Current Fiscal Year	16.9	124.7
Financing Receivable, before Allowance for Credit Loss	1,392.6	1,348.7
Financing Receivable, Allowance for Credit Loss	(3)	(2.6)	$ (3.4)
Commercial Real Estate | Loan To Value Ratio Above 65 To 75 Percent
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	230.2	115.7
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	181.6	115.4
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	150.9	215.4
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	80.1	280.1
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	227.5	126.4
Financing Receivable, Year One, Originated, Current Fiscal Year	71.7	228.5
Financing Receivable, before Allowance for Credit Loss	942	1,081.5
Financing Receivable, Allowance for Credit Loss	(4.7)	(4.7)	(7.3)
Commercial Real Estate | Loan To Value Ratio Above 75 To 85 Percent
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	67.5	89.3
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0	26.3
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	8.5	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, before Allowance for Credit Loss	76	115.6
Financing Receivable, Allowance for Credit Loss	(1.1)	(0.7)	(1.3)
Commercial Real Estate | Loan To Value Ratio Above 85 Percent
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	28.2	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	5.9	16.9
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	6
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, before Allowance for Credit Loss	34.1	22.9
Financing Receivable, Allowance for Credit Loss	(0.5)	(0.3)	$ (1.1)
Commercial Real Estate | Originated Five or More Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Financing Receivable, Allowance for Credit Loss	(4.3)	(2.6)
Commercial Real Estate | Originated Four Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Financing Receivable, Allowance for Credit Loss	(1.8)	(1.4)
Commercial Real Estate | Originated Three Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Financing Receivable, Allowance for Credit Loss	(1.3)	(1.4)
Commercial Real Estate | Originated Two Years before Last Fiscal Year
Financing Receivable, Credit Quality Indicator
Financing Receivable, Allowance for Credit Loss	(0.6)	(1.4)
Commercial Real Estate | Originated in Fiscal Year before Latest Fiscal Year
Financing Receivable, Credit Quality Indicator
Financing Receivable, Allowance for Credit Loss	(0.8)	(0.7)
Commercial Real Estate | Originated in Current Fiscal Year
Financing Receivable, Credit Quality Indicator
Financing Receivable, Allowance for Credit Loss	(0.5)	(0.8)
Commercial Real Estate | AA Credit Rating
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	53.8	3.3
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	27.5	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	11.1	24
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, before Allowance for Credit Loss	92.4	27.3
Commercial Real Estate | A Credit Rating
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	485	414.6
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	123.3	68
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	96.8	71.1
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	35.9	28.9
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	80.6	17.6
Financing Receivable, Year One, Originated, Current Fiscal Year	24	110.6
Financing Receivable, before Allowance for Credit Loss	845.6	710.8
Commercial Real Estate | BBB Credit Rating
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	534	561.2
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	219.8	227.3
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	236.9	283.3
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	134	331.9
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	275.8	163.1
Financing Receivable, Year One, Originated, Current Fiscal Year	64.6	242.6
Financing Receivable, before Allowance for Credit Loss	1,465.1	1,809.4
Commercial Real Estate | BB Credit Rating
Financing Receivable, Credit Quality Indicator
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	35.7	5
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	5.9	10.2
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	6
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, before Allowance for Credit Loss	$ 41.6	$ 21.2

Mortgage Loans, Allowance for C

Mortgage Loans, Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss
Financing Receivable, Allowance for Credit Loss, Ending Balance	$ 9.3
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss
Financing Receivable, Allowance for Credit Loss, Beginning Balance	8.3
Financing Receivable, Allowance for Credit Loss, Ending Balance	9.3	$ 8.3
Commercial Real Estate | Loan to Value Ratio Below or Equal to 65 Percent
Financing Receivable, Allowance for Credit Loss
Financing Receivable, Allowance for Credit Loss, Beginning Balance	2.6	3.4
Financing Receivable, Credit Loss, Expense (Reversal)	0.4	(0.8)
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Loss, Recovery	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	3	2.6
Commercial Real Estate | Loan To Value Ratio Above 65 To 75 Percent
Financing Receivable, Allowance for Credit Loss
Financing Receivable, Allowance for Credit Loss, Beginning Balance	4.7	7.3
Financing Receivable, Credit Loss, Expense (Reversal)	0	(2.6)
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Loss, Recovery	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	4.7	4.7
Commercial Real Estate | Loan To Value Ratio Above 75 To 85 Percent
Financing Receivable, Allowance for Credit Loss
Financing Receivable, Allowance for Credit Loss, Beginning Balance	0.7	1.3
Financing Receivable, Credit Loss, Expense (Reversal)	0.4	(0.6)
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Loss, Recovery	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	1.1	0.7
Commercial Real Estate | Loan To Value Ratio Above 85 Percent
Financing Receivable, Allowance for Credit Loss
Financing Receivable, Allowance for Credit Loss, Beginning Balance	0.3	1.1
Financing Receivable, Credit Loss, Expense (Reversal)	0.2	(0.8)
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Loss, Recovery	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	0.5	0.3
Commercial Real Estate | Loan to Value Ratio Total
Financing Receivable, Allowance for Credit Loss
Financing Receivable, Allowance for Credit Loss, Beginning Balance	8.3	13.1
Financing Receivable, Credit Loss, Expense (Reversal)	1	(4.8)
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Loss, Recovery	0	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	$ 9.3	$ 8.3

Investments Remaining Contractu

Investments Remaining Contractual Maturity of Security Lending Agreements (Details) - Overnight and Continuous - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	$ 88.5	$ 94.8
Securities Loaned and Securities Sold under Agreement to Repurchase, Gross Including Not Subject to Master Netting Arrangement	88.5	94.8
Secured Borrowings, Gross, Difference, Amount	0	0
United States Government and Government Agencies and Authorities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0.3	0.1
States, Municipalities, and Political Subdivisions
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0	0.1
Public Utilities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	6.3	3.1
All Other Corporate Bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	$ 81.9	$ 91.5

Investments Federal Home Loan B

Investments Federal Home Loan Bank Carrying Amount, Collateral Posted and Advances Received (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Federal Home Loan Bank Common Stock	$ 17.1	$ 22.1
Federal Home Loan Bank, Advances	99.1	160.9
Federal Home Loan Bank, Collateral Posted to FHLB	1,329	1,716.1
Fixed Maturity Securities
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Federal Home Loan Bank, Collateral Posted to FHLB	527.1	786.1
Commercial Mortgage Loans
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Federal Home Loan Bank, Collateral Posted to FHLB	$ 801.9	$ 930

Investments Schedule of Financi

Investments Schedule of Financial Instrument and Derivative Offsetting (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Offsetting Derivative Assets
Derivative Asset, Fair Value, Gross Asset	$ 89.1	$ 39.5
Derivative Liabilities Offsetting Derivative Assets in Balance Sheet	0	0
Net Derivative Assets Reported in Balance Sheet	89.1	39.5
Securities Received as Collateral on Derivative Assets	(38)	(9.8)
Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset	(49.4)	(28.4)
Derivative Assets Net of Collateral	1.7	1.3
Offsetting Securities Borrowed
Securities Received as Collateral on Securities Borrowed	(88.5)	(94.8)
Cash Received as Collateral on Securities Borrowed	0	0
Offsetting Financial Assets
Gross Financial Assets	241.5	323.2
Financial Liabilities Offsetting Financial Assets in Balance Sheet	0	0
Net Financial Assets Reported in Balance Sheet	241.5	323.2
Securities Received as Collateral on Financial Assets	(101.9)	(198.7)
Cash Received as Collateral on Financial Assets	(137.9)	(123.2)
Financial Assets Net of Collateral	1.7	1.3
Offsetting Derivative Liabilities
Net Derivative Liabilities Reported in Balance Sheet		65.1
Offsetting Securities Loaned
Gross Securities Loaned	(152.4)	(283.7)
Assets Offsetting Securities Loaned in Balance Sheet	0	0
Securities Loaned	(152.4)	(283.7)
Securities Given as Collateral on Securities Loaned	(63.9)	(188.9)
Cash Given as Collateral on Securities Loaned	(88.5)	(94.8)
Securities Loaned Net of Collateral	0	0
Offsetting Financial Liabilities
Gross Financial Liability	162.5	129.8
Financial Assets Offsetting Financial Liabilities in Balance Sheet	0	0
Net Financial Liabilities Reported in Balance Sheet	162.5	129.8
Securities Given as Collateral on Financial Liabilities	(161.7)	(128.8)
Cash Given as Collateral on Financial Liabilities	0	0
Financial Liabilities Net of Collateral	0.8	1
Security Borrowed, Subject to Master Netting Arrangement, before Offset	88.5	94.8
Security Borrowed, Subject to Master Netting Arrangement, Liability Offset	0	0
Securities Borrowed	88.5	94.8
Security Borrowed, Including Not Subject to Master Netting Arrangement, after Offset and Deduction	0	0
Miscellaneous Long-term Investments
Offsetting Derivative Assets
Derivative Asset, Fair Value, Gross Asset	89.1	39.5
Over the Counter
Offsetting Derivative Liabilities
Gross Derivative Liability	74	35
Derivative Assets Offsetting Derivative Liabilities in Balance Sheet	0	0
Net Derivative Liabilities Reported in Balance Sheet	74	35
FMS Collateral Posted to Counterparties	(73.2)	(34)
Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset	0	0
Derivative Liabilities Net of Collateral	$ 0.8	$ 1

Investments Investment Income (

Investments Investment Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Net Investment Income
Investment Income, Interest and Dividend	$ 2,173.6		$ 2,260.6		$ 2,403.7
Less Investment Expenses	39.4		35.1		30.6
Less Investment Income on PFA Assets	12		12.3		12.4
Net Investment Income	2,122.2		2,213.2		2,360.7
Fixed Maturity Securities
Net Investment Income
Investment Income, Interest and Dividend	1,849.8		1,888.2		2,164
Derivatives
Net Investment Income
Investment Income, Interest and Dividend	57.8		68.6		78.7
Mortgage Loans
Net Investment Income
Investment Income, Interest and Dividend	101.5		105		108.9
Policy Loans
Net Investment Income
Investment Income, Interest and Dividend	20		19.7		20
Perpetual Preferred Securities
Net Investment Income
Investment Income, Interest and Dividend	5	[1]	6.9	[1]	(2.1)
Private Equity Partnerships
Net Investment Income
Investment Income, Interest and Dividend	110.1		165.4		19.8
Other Long-term Investments
Net Investment Income
Investment Income, Interest and Dividend	9.4		5.5		3.9
Short-term Investments
Net Investment Income
Investment Income, Interest and Dividend	$ 20		$ 1.3		$ 10.5
[1]The net unrealized gain (loss) recognized in net investment income for the year ended December 31, 2022 related to perpetual preferred securities still held at December 31, 2022 was $2.8 million. The net unrealized gain (loss) recognized in net investment income for the years ended December 31, 2021 and 2020 related to perpetual preferred securities still held at year-end was $4.4 million and $(4.6) million, respectively

Investment Gains and Losses Rep

Investment Gains and Losses Reported in Consolidated Statements of Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022		Dec. 31, 2021	Dec. 31, 2020
Fixed Maturity Securities
Debt Securities, Available-for-sale, Realized Gain	$ 2.3	[1]	$ 76.2	$ 1,332.8
Gross Losses on Sales	(28.8)		(11.5)	(20.3)
Credit Losses	(4.6)		(9.3)	(53.6)
Mortgage Loans and Other Invested Assets
Gross Gains on Sales	1.4		5.8	1.9
Gross Losses on Sales	0		0	(0.3)
Impairment Loss	0		0	(36.6)
Credit Losses	(1)		4.7	(4.6)
Gain (Loss) on Embedded Derivative	16.2		9.7	(17)
All Other Derivatives	2.6		3.1	(2.5)
Foreign Currency Transactions	(3.8)		(2)	(0.7)
Net Investment Gain (Loss)	$ (15.7)		$ 76.7	$ 1,199.1
[1]Gross gains on sales of fixed maturity securities for the year ended December 31, 2021 includes gains of $67.6 million as a result of the second phase of the reinsurance transaction that we completed during the first quarter of 2021. Gross gains on sales of fixed maturity securities for the year ended December 31, 2020 includes gains of $1,302.3 million as a result of the first phase of the reinsurance transaction that we completed during the fourth quarter of 2020. See Note 12 for further discussion.

Investments - Additional Inform

Investments - Additional Information (Detail)		12 Months Ended
		Dec. 31, 2022 USD ($) Integer	Dec. 31, 2021 USD ($) Integer	Dec. 31, 2020 USD ($) Integer
Schedule of Investments
Other Long-term Investments		$ 1,440,100,000	$ 1,203,000,000
Unfunded Commitments		700,000
Financing Receivable, Allowance for Credit Losses		9,300,000
Accrued Investment Income		615,000,000	602,700,000
Foreclosed Real Estate Expense		0	0	$ 0
Committments to Fund Commercial Mortgage Loans		5,000,000	26,300,000
Real Estate Investment Property, Net		71,600,000	119,500,000
Real Estate Investment Property, Accumulated Depreciation		122,100,000	171,300,000
Impairment of Real Estate		0	0	36,600,000
Real Estate Held-for-sale		$ 40,900,000
Repurchase agreements - Typical Days outstanding		30
Minimum percent of the fair value of securities loaned or securities purchased under repurchase agreements be maintained as collateral		102%
Gross Securities Loaned		$ 152,400,000	283,700,000
Outstanding Repurchase Agreements		0	0
Financing Receivable, Troubled Debt Restructuring, Postmodification		8,000,000
Securities Loaned		152,400,000	283,700,000
Net Investment Gain (Loss)		(15,700,000)	76,700,000	1,199,100,000
Real Estate Investment
Schedule of Investments
Net Investment Gain (Loss)		0
Perpetual Preferred Securities
Schedule of Investments
Unrealized Gain (Loss) on Investments	[1]	2,800,000	4,400,000	$ (4,600,000)
Off Balance Sheet Amount
Schedule of Investments
Cash Collateral for Borrowed Securities		88,500,000	94,800,000
Securities Received as Collateral		69,800,000	198,600,000
Commercial Real Estate
Schedule of Investments
Financing Receivable, before Allowance for Credit Loss		2,444,700,000	2,568,700,000
Financing Receivable, Allowance for Credit Losses		9,300,000	8,300,000
Accrued Investment Income		$ 7,700,000	$ 8,100,000
Financing Receivable, Modifications, Number of Contracts | Integer		0	0	0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		$ 0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	$ 0	$ 0
Unfunded Mortgage Loan Commitments
Schedule of Investments
Allowance for Credit Losses, Unfunded Mortgage Loan Commitments			100,000
Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments
Other Long-term Investments		1,195,300,000	987,900,000
Tax Credit Partnership | Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments
Other Long-term Investments		1,000,000	9,300,000
Private Equity Partnerships | Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments
Other Long-term Investments		1,194,300,000	978,600,000
Investment Real Estate
Schedule of Investments
Impairment of Real Estate		0	$ 0
Private Placement Fixed Maturity
Schedule of Investments
Fair Value Disclosure, off-Balance-Sheet Risks, Amount, Liability		58,700,000
Public Utilities | Principal Forgiveness
Schedule of Investments
Financing Receivable, Troubled Debt Restructuring		4,800,000
Private Equity Partnerships
Schedule of Investments
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 4,900,000
External Credit Rating, Investment Grade
Schedule of Investments
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions		882
Number of Fixed Maturity Securities in an Unrealized Loss Position Continuously for Over One Year		262
External Credit Rating, Below-Investment-Grade
Schedule of Investments
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions		112
Number of Fixed Maturity Securities in an Unrealized Loss Position Continuously for Over One Year		16
[1] The net unrealized gain (loss) recognized in net investment income for the year ended December 31, 2022 related to perpetual preferred securities still held at December 31, 2022 was $2.8 million. The net unrealized gain (loss) recognized in net investment income for the years ended December 31, 2021 and 2020 related to perpetual preferred securities still held at year-end was $4.4 million and $(4.6) million, respectively

Derivative Financial Instrume_3

Derivative Financial Instruments Nature and Amount of Collateral Received From and Posted To Our Derivative Counterparties (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative
Cash Collateral from Counterparties	$ 49.4	$ 28.4
Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset	44.7	27.6
Cash
Derivative
Cash Collateral from Counterparties	49.4	32
Cash Collateral Posted to Counterparties	5.1	0
Fixed Maturity Securities
Derivative
FMS Collateral Posted to Counterparties	$ 39.6	$ 27.6

Derivative Financial Instrume_4

Derivative Financial Instruments Fair Value Hedges Carrying Amount of Hedged Assets and Liabilities and Cumulative Basis Adjustments (Details) - Interest Rate Swaps - Receive Fixed/Pay Fixed - Designated as Hedging Instrument - Fair Value Hedging - Fixed Maturity Securities - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosures
Hedged Asset, Fair Value Hedge	$ 394.4	$ 466.3
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	$ (24.8)	$ 2

Location and Fair Values of Der

Location and Fair Values of Derivative Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative
Derivative, Notional Amount	$ 1,753.9	$ 970.5
Asset Derivatives Fair Value	89.1	39.5
Other Long-term Investments
Derivative
Asset Derivatives Fair Value	89.1	39.5
Other Liabilities
Derivative
Liability Derivatives Fair Value	87.9	65.1
Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	1,490.7	679.8
Designated as Hedging Instrument | Cash Flow Hedging
Derivative
Derivative, Notional Amount	932.9
Designated as Hedging Instrument | Forwards | Cash Flow Hedging
Derivative
Derivative, Notional Amount	764
Designated as Hedging Instrument | Interest Rate Swaps | Cash Flow Hedging
Derivative
Derivative, Notional Amount	168.9	181.3
Designated as Hedging Instrument | Interest Rate Swaps | Fair Value Hedging
Derivative
Derivative, Notional Amount	557.8	498.5
Designated as Hedging Instrument | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	85.1	38.1
Designated as Hedging Instrument | Other Long-term Investments | Cash Flow Hedging
Derivative
Asset Derivatives Fair Value	19.1
Designated as Hedging Instrument | Other Long-term Investments | Forwards | Cash Flow Hedging
Derivative
Asset Derivatives Fair Value	1.6
Designated as Hedging Instrument | Other Long-term Investments | Interest Rate Swaps | Cash Flow Hedging
Derivative
Asset Derivatives Fair Value	17.5	16.2
Designated as Hedging Instrument | Other Long-term Investments | Interest Rate Swaps | Fair Value Hedging
Derivative
Asset Derivatives Fair Value	66	21.9
Designated as Hedging Instrument | Other Liabilities
Derivative
Liability Derivatives Fair Value	56.9	12.7
Designated as Hedging Instrument | Other Liabilities | Cash Flow Hedging
Derivative
Liability Derivatives Fair Value	51.5
Designated as Hedging Instrument | Other Liabilities | Forwards | Cash Flow Hedging
Derivative
Liability Derivatives Fair Value	48.4
Designated as Hedging Instrument | Other Liabilities | Interest Rate Swaps | Cash Flow Hedging
Derivative
Liability Derivatives Fair Value	3.1	7
Designated as Hedging Instrument | Other Liabilities | Interest Rate Swaps | Fair Value Hedging
Derivative
Liability Derivatives Fair Value	5.4	5.7
Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	263.2	290.7
Not Designated as Hedging Instrument | Forwards
Derivative
Derivative, Notional Amount	54.3	41.7
Not Designated as Hedging Instrument | Interest Rate Swaps
Derivative
Derivative, Notional Amount	132	148.2
Not Designated as Hedging Instrument | Total Return Swap
Derivative
Derivative, Notional Amount	76.9	89.2
Not Designated as Hedging Instrument | Embedded Derivative in Modified Coinsurance Arrangement
Derivative
Derivative, Notional Amount	0	0
Not Designated as Hedging Instrument | Credit Default Swaps
Derivative
Derivative, Notional Amount		11.6
Not Designated as Hedging Instrument | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	4	1.4
Not Designated as Hedging Instrument | Other Long-term Investments | Forwards
Derivative
Asset Derivatives Fair Value	4	0
Not Designated as Hedging Instrument | Other Long-term Investments | Interest Rate Swaps
Derivative
Asset Derivatives Fair Value	0	1.4
Not Designated as Hedging Instrument | Other Long-term Investments | Total Return Swap
Derivative
Asset Derivatives Fair Value	0	0
Not Designated as Hedging Instrument | Other Long-term Investments | Embedded Derivative in Modified Coinsurance Arrangement
Derivative
Asset Derivatives Fair Value	0	0
Not Designated as Hedging Instrument | Other Long-term Investments | Credit Default Swaps
Derivative
Asset Derivatives Fair Value		0
Not Designated as Hedging Instrument | Other Liabilities
Derivative
Liability Derivatives Fair Value	31	52.4
Not Designated as Hedging Instrument | Other Liabilities | Forwards
Derivative
Liability Derivatives Fair Value	0.1	0
Not Designated as Hedging Instrument | Other Liabilities | Interest Rate Swaps
Derivative
Liability Derivatives Fair Value	17	22.3
Not Designated as Hedging Instrument | Other Liabilities | Total Return Swap
Derivative
Liability Derivatives Fair Value	0	0
Not Designated as Hedging Instrument | Other Liabilities | Embedded Derivative in Modified Coinsurance Arrangement
Derivative
Liability Derivatives Fair Value	$ 13.9	30.1
Not Designated as Hedging Instrument | Other Liabilities | Credit Default Swaps
Derivative
Liability Derivatives Fair Value		$ 0

Derivative Financial Instrume_5

Derivative Financial Instruments Location of Gains and Losses Designated as Hedging Instruments, Consolidated Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments, Gain (Loss)
Net Investment Income	$ 2,122.2	$ 2,213.2	$ 2,360.7
Net Investment Gain (Loss)	(15.7)	76.7	1,199.1
Interest and Debt Expense	188.5	185	188.2
Derivative, Gain (Loss) on Derivative, Net	(2.6)	(3.1)	2.5
Designated as Hedging Instrument | Interest Rate Swaps | Net Investment Income | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	200	220.4	286.1
Derivative, Gain (Loss) on Derivative, Net	51	64.6	75.9
Designated as Hedging Instrument | Interest Rate Swaps | Net Investment Income | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income			0
Derivative, Gain (Loss) on Derivative, Net			0
Designated as Hedging Instrument | Interest Rate Swaps | Net Realized Investment Gain (Loss) | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	0	2.7	397.7
Derivative, Gain (Loss) on Derivative, Net	0	2	32
Designated as Hedging Instrument | Interest Rate Swaps | Net Realized Investment Gain (Loss) | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)			(0.6)
Derivative, Gain (Loss) on Derivative, Net			0.6
Designated as Hedging Instrument | Interest Rate Swaps | Interest and Debt Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	2.9	29.2	29.2
Derivative, Gain (Loss) on Derivative, Net	0	5	1.7
Designated as Hedging Instrument | Interest Rate Swaps | Interest and Debt Expense | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense			10.1
Derivative, Gain (Loss) on Derivative, Net			(0.9)
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Investment Income | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	12.3	13	12.1
Derivative, Gain (Loss) on Derivative, Net	(0.8)	1.8	2.5
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Investment Income | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	11.6	9.8	7.1
Derivative, Gain (Loss) on Derivative, Net	7.3	4.6	2.8
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Realized Investment Gain (Loss) | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	(2.3)	(0.1)	(0.1)
Derivative, Gain (Loss) on Derivative, Net	1.8	(0.1)	0.1
Designated as Hedging Instrument | Foreign Exchange Contracts | Net Realized Investment Gain (Loss) | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	(26.8)	(22.3)	23.3
Derivative, Gain (Loss) on Derivative, Net	26.8	22.3	(23.3)
Designated as Hedging Instrument | Foreign Exchange Contracts | Interest and Debt Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	0	0	0
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Designated as Hedging Instrument | Foreign Exchange Contracts | Interest and Debt Expense | Fair Value Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	0	0	0
Derivative, Gain (Loss) on Derivative, Net	0	$ 0	$ 0
Designated as Hedging Instrument | Forwards | Net Investment Income | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Income	0.5
Designated as Hedging Instrument | Forwards | Net Realized Investment Gain (Loss) | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Net Investment Gain (Loss)	0
Designated as Hedging Instrument | Forwards | Interest and Debt Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss)
Interest and Debt Expense	$ 0

Location of Gains and Losses on

Location of Gains and Losses on Derivative Instruments Designated as Cash Flow Hedging Instruments (Detail) - Designated as Hedging Instrument - Cash Flow Hedging - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments, Gain (Loss)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ (42.4)	$ 1.6	$ (5.4)
Forwards
Derivative Instruments, Gain (Loss)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	(49.8)	(0.6)	0
Foreign Exchange Contracts
Derivative Instruments, Gain (Loss)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ 7.4	$ 2.2	$ (5.4)

Gains and Losses on Derivatives

Gains and Losses on Derivatives Not Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	$ 2.6	$ 3.1	$ (2.5)
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	18.9	12.8	(19.5)
Credit Default Swaps | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	0	(0.3)	(0.5)
Foreign Exchange Contracts | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	2.7	3.4	(2)
Embedded Derivative in Modified Coinsurance Arrangement | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	16.2	9.7	(17)
Total Return Swap | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Net Gain (Loss) on Derivatives	$ 18.9	$ (8.5)	$ 0

Derivative Financial Instrume_6

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative
Aggregate fair value of all derivative instruments with credit risk-related contingent features in a liability position	$ 74	$ 35
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net		0.6	$ 30.7
Approximate amount of net deferred gains on derivative instruments expected to be amortized during the next twelve months	35.4
Component of Derivative Gain (Loss) Excluded from the Assessment of Hedge Effectiveness	17.6	16.6	(1.8)
Discontinued Hedge Accounting Due to Instrument No Longer Qualifying as Fair Value Hedge	0	0	$ 0
Derivative, Notional Amount	1,753.9	970.5
Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	1,490.7	679.8
Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	263.2	290.7
Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	932.9
Interest Rate Swaps | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	132	148.2
Interest Rate Swaps | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	168.9	181.3
Interest Rate Swaps | Fair Value Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	557.8	498.5
Credit Risk Contract | Credit Default Swaps | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	0	11.6
Forwards | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	54.3	41.7
Forwards | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	764
Derivative, Loss on Derivative	1.2
Notional Amount Of Derivatives Terminations		250
Notional Amount Of Derivatives Additions	779	250
Total Return Swap | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	76.9	89.2
Receive Fixed/Pay Fixed | Interest Rate Swaps | Not Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	132	148.2
Receive Fixed/Pay Fixed | Interest Rate Swaps | Cash Flow Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	168.9	181.3
Receive Fixed/Pay Fixed | Interest Rate Swaps | Fair Value Hedging | Designated as Hedging Instrument
Derivative
Derivative, Notional Amount	557.8	498.5
Credit Exposure
Derivative
Credit Exposure on Derivatives	$ 1.7	$ 1.3

Schedule of Accumulated Other C

Schedule of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (2,756.6)	$ 354.1	$ 374.2	$ 37.3
Other Comprehensive Income (Loss) Before Reclassifications	(3,105.1)	(51.5)	359.4
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	5.6	(31.4)	22.5
Total Other Comprehensive Income (Loss)	(3,110.7)	(20.1)	336.9
Net Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(2,023.8)	962.2	1,067.7	615.9
Other Comprehensive Income (Loss) Before Reclassifications	(3,009.2)	(169.9)	405.6
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	(23.2)	(64.4)	(46.2)
Total Other Comprehensive Income (Loss)	(2,986)	(105.5)	451.8
Net Gain on Hedges
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(9.6)	61.8	97.8	187.8
Other Comprehensive Income (Loss) Before Reclassifications	(30.4)	14.7	(5.7)
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	41	50.7	84.3
Total Other Comprehensive Income (Loss)	(71.4)	(36)	(90)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(389.1)	(273.9)	(261.3)	(281.6)
Other Comprehensive Income (Loss) Before Reclassifications	(115.2)	(12.6)	20.3
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	0	0	0
Total Other Comprehensive Income (Loss)	(115.2)	(12.6)	20.3
Unrecognized Pension and Postretirement Benefit Costs
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(334.1)	(396)	(530)	$ (484.8)
Other Comprehensive Income (Loss) Before Reclassifications	49.7	116.3	(60.8)
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	(12.2)	(17.7)	(15.6)
Total Other Comprehensive Income (Loss)	$ 61.9	$ 134	$ (45.2)

Schedule of Components of Unrea

Schedule of Components of Unrealized Gain (Loss) on Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in Components of Net Unrealized Gain on Securities
Change in Net Unrealized Gain on Securities	$ (7,042.9)	$ (1,301.4)	$ 983
Fixed Maturity Securities
Change in Components of Net Unrealized Gain on Securities
Beginning of Year Balance	5,949.3	7,597.6	6,364.4
Change in Net Unrealized Gain on Securities	(8,933.7)	(1,648.3)	1,233.2
End of Year Balance	(2,984.4)	5,949.3	7,597.6
Deferred Acquisition Costs
Change in Components of Net Unrealized Gain on Securities
Beginning of Year Balance	(70.4)	(85.1)	(62.7)
Change in Net Unrealized Gain on Securities	81.7	14.7	(22.4)
End of Year Balance	11.3	(70.4)	(85.1)
Reserve for Future Policy and Contract Benefits
Change in Components of Net Unrealized Gain on Securities
Beginning of Year Balance	(4,659.5)	(6,225.6)	(5,803.1)
Change in Net Unrealized Gain on Securities	5,226.2	1,566.1	(422.5)
End of Year Balance	566.7	(4,659.5)	(6,225.6)
Reinsurance Recoverable
Change in Components of Net Unrealized Gain on Securities
Beginning of Year Balance	132.1	200.2	424.7
Change in Net Unrealized Gain on Securities	(150.2)	(68.1)	(224.5)
End of Year Balance	(18.1)	132.1	200.2
Income Tax
Change in Components of Net Unrealized Gain on Securities
Beginning of Year Balance	(389.3)	(419.4)	(307.4)
Change in Net Unrealized Gain on Securities	790	30.1	(112)
End of Year Balance	400.7	(389.3)	(419.4)
Net Unrealized Gain (Loss) on Securities
Change in Components of Net Unrealized Gain on Securities
Beginning of Year Balance	962.2	1,067.7	615.9
Change in Net Unrealized Gain on Securities	(2,986)	(105.5)	451.8
End of Year Balance	$ (2,023.8)	$ 962.2	$ 1,067.7

Schedule of Reclassifications O

Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Gain (Loss)	$ (15.7)	$ 76.7	$ 1,199.1
Benefits and Change in Reserves for Future Benefits	(6,936.7)	(7,598.6)	(8,972.9)
Net Investment Income	2,122.2	2,213.2	2,360.7
Interest and Debt Expense	(188.5)	(185)	(188.2)
Other Expenses	(1,020.2)	(1,008.6)	(996.6)
Income Tax Expense (Benefit)	317.2	238.8	171
Net Income	1,314.2	824.2	793
Reclassification out of Accumulated Other Comprehensive Income | Net Unrealized Gain (Loss) on Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Gain (Loss)	(24.8)	60.8	1,279.7
Other-Than-Temporary Impairment Loss	(4.6)	(9.3)	(53.6)
Benefits and Change in Reserves for Future Benefits	0	(133.1)	(1,284.5)
Income Before Income Tax	(29.4)	(81.6)	(58.4)
Income Tax Expense (Benefit)	(6.2)	(17.2)	(12.2)
Net Income	(23.2)	(64.4)	(46.2)
Reclassification out of Accumulated Other Comprehensive Income | Net Gain on Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Income Before Income Tax	51.9	64.2	106.7
Income Tax Expense (Benefit)	10.9	13.5	22.4
Net Income	41	50.7	84.3
Reclassification out of Accumulated Other Comprehensive Income | Net Gain on Hedges | Interest Rate Swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Gain (Loss)	0	2	32
Net Investment Income	51.1	60.6	74.1
Interest and Debt Expense	0	0	(1.5)
Reclassification out of Accumulated Other Comprehensive Income | Net Gain on Hedges | Foreign Exchange Contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Net Investment Gain (Loss)	1.8	(0.1)	0.1
Net Investment Income	(1)	1.7	2
Reclassification out of Accumulated Other Comprehensive Income | Net Actuarial Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other Expenses	(15.7)	(22.6)	(19.8)
Reclassification out of Accumulated Other Comprehensive Income | Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other Expenses	0.2	0.2	0.1
Reclassification out of Accumulated Other Comprehensive Income | Curtailment Gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other Expenses	0	0	(0.1)
Reclassification out of Accumulated Other Comprehensive Income | Unrecognized Pension and Postretirement Benefit Costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Income Before Income Tax	(15.5)	(22.4)	(19.8)
Income Tax Expense (Benefit)	(3.3)	(4.7)	(4.2)
Net Income	$ (12.2)	$ (17.7)	$ (15.6)

Liability for Unpaid Claims a_3

Liability for Unpaid Claims and Claims Adjustment Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense
Balance at January 1	$ 23,664.7	$ 24,180.2	$ 23,076.7
Less Reinsurance Recoverable	8,697.8	8,378.9	2,246.8
Net Balance at January 1	14,966.9	15,801.3	20,829.9
Incurred Related to
Current Year	6,721.3	7,252.6	6,327.8
Paid Related to
Current Year	(3,062.9)	(3,263.4)	(2,727)
Prior Years	(3,786)	(3,774.1)	(4,430.3)
Total Paid	(6,848.9)	(7,037.5)	(7,157.3)
Reserves Ceded Pursuant to Reinsurance Transaction	0	(990)	(6,141.5)
Net Balance at December 31	14,553	14,966.9	15,801.3
Plus Reinsurance Recoverable	8,279.8	8,697.8	8,378.9
Balance at December 31	22,832.8	23,664.7	24,180.2
Amount Related to Interest
Incurred Related to
Prior Years	595.6	683.4	997.8
Incurred Claims
Incurred Related to
Prior Years	(646)	(719.5)	878.7
Foreign Currency
Incurred Related to
Prior Years	(235.9)	(23.4)	65.9
Operating Expense
Incurred Related to
Total Incurred	$ 6,435	$ 7,193.1	$ 8,270.2

Reconciliation of Policy and Co

Reconciliation of Policy and Contract Benefits and Reserves for Future Policy and Contract Benefits (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Insurance [Abstract]
Policy and Contract Benefits	$ 1,839.8	$ 1,907.7	$ 1,855.4
Reserves for Future Policy and Contract Benefits	42,330.2	48,007.5	49,653
Total Policy and Contract Benefits and Reserves for Future Policy and Contract Benefits	44,170	49,915.2	51,508.4
Life Reserves for Future Policy and Contract Benefits	8,428.5	8,457.1	8,371.7
Accident and Health Active Life Reserves	13,475.4	13,133.9	12,730.9
Adjustment Related to Unrealized Investment Gains and Losses	(566.7)	4,659.5	6,225.6
Liability for Unpaid Claims and Claim Adjustment Expense	$ 22,832.8	$ 23,664.7	$ 24,180.2	$ 23,076.7

Liability for Unpaid Claims - A

Liability for Unpaid Claims - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Mar. 31, 2021	Dec. 16, 2020	Dec. 31, 2019
Liability for Unpaid Claims and CAE Narrative Information
Unum US Group Long-term Disability Reserve Reduction, Before Tax	$ 121	$ 215
Closed Block Long-term Care Reserve Increase, Before Tax		2.1
Closed Block Individual Disability Reserve Increase, Before Tax		6.4
Net Reduction in Unpaid Claims as a Result of Assumption Updates, Before Tax	155	206.5
Long-term Care Reserve Increase, Before Tax			$ 151.5
Reinsurance Recoverables, Incurred but Not Reported Claims	8,279.8	8,697.8	8,378.9			$ 2,246.8
Unum US Group Life Reserve Reduction, Before Tax	$ 34
Closed Block Individual Disability Reinsurance Transaction
Liability for Unpaid Claims and CAE Narrative Information
Increase in Benefits and Change in Reserves for Future Benefits		133.1	1,284.5
Reinsurance Recoverables, Incurred but Not Reported Claims				$ 990	$ 6,141.5
Closed Block Individual Disability Reinsurance Transaction | Phase 1
Liability for Unpaid Claims and CAE Narrative Information
Increase in Benefits and Change in Reserves for Future Benefits			1,284.5
Reinsurance Recoverables, Incurred but Not Reported Claims			6,141.5
Closed Block Individual Disability Reinsurance Transaction | Phase 2
Liability for Unpaid Claims and CAE Narrative Information
Increase in Benefits and Change in Reserves for Future Benefits		133.1
Reinsurance Recoverables, Incurred but Not Reported Claims		$ 990
Claim Reserve
Liability for Unpaid Claims and CAE Narrative Information
Long-term Care Reserve Increase, Before Tax			$ 7

Income Tax Expense (Benefit) (D

Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax [Abstract]
Income Tax Expense	$ 317.2	$ 238.8	$ 171
Other Comprehensive Income (Loss), Tax
Change in Net Unrealized Gain on Securities Before Adjustment	(1,890.8)	(346.9)	250.2
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance	1,100.8	316.8	(138.2)
Change in Net Gain on Hedges	(19.2)	(9.8)	(23.8)
Change in Foreign Currency Translation Adjustment	(0.1)	4.2	(4.3)
Change in Unrecognized Pension and Postretirement Benefit Costs	18.9	42.1	(34.8)
Total	$ (473.2)	$ 245.2	$ 220.1

Reconciliation of income tax co

Reconciliation of income tax computed at US Federal tax rates (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax [Abstract]
Statutory Income Tax	21%	21%	21%
Net Operating Loss Carryback	0%	(0.70%)	(3.80%)
Tax Exempt Income	(1.10%)	(1.10%)	(0.80%)
Tax Credits	(0.30%)	(0.90%)	(1.30%)
Policyholder Reserves	(1.90%)	2.40%	0.70%
Other Items, Net	1.70%	1.80%	1.90%
Effective Tax	19.40%	22.50%	17.70%

Schedule of deferred income tax

Schedule of deferred income tax assets and liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Income Tax [Abstract]
Deferred Tax Assets, Investments	$ 664.9	$ 0
Deferred Tax Asset, Reserves	0	889.7
Deferred Tax Asset, Employee Benefits	158.3	176.6
Deferred Tax Asset, Other	34.4	57.5
Deferred Tax Assets, Gross, Total	857.6	1,123.8
Less: Valuation Allowance	10.3	12.7
Deferred Tax Assets, Net of Valuation Allowance, Total	847.3	1,111.1
Deferred Tax Liabilities for Deferred Acquisition Cost	113.1	134.9
Deferred Tax Liabilities for Fixed Assets	48.9	71.1
Deferred Tax Liabilities on Invested Assets	0	1,144.9
Deferred Tax Liabilities, Other Comprehensive Income	43.2	0
Deferred Tax Liabilities on Cost of Reinsurance	156.8	171.6
Deferred Tax Liability, Other	44.7	47
Gross Deferred Tax Liability	406.7	1,569.5
Deferred Income Tax	$ 440.6
Deferred Tax Liabilities, Net, Total		$ (458.4)

Schedule of Income subject to d

Schedule of Income subject to domestic and foreign taxation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax [Abstract]
Income Before Tax, Domestic	$ 1,492.8	$ 957	$ 924.7
Income Before Tax, Foreign	138.6	106	39.3
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	1,631.4	1,063	964
Current Tax Expense (Benefit), Domestic	306.5	180.7	(98.4)
Current State and Local Tax Expense (Benefit)	12.7	2.6	1.5
Current Tax Expense (Benefit), Foreign	154.3	29.5	(19.7)
Income Tax (Benefit) - Current	473.5	212.8	(116.6)
Deferred Tax Expense (Benefit), Federal	20.9	13.3	250.5
Deferred State and Local Income Tax Expense (Benefit)	1.1	(2.2)	1
Deferred Tax Expense (Benefit), Foreign	(178.3)	14.9	36.1
Deferred Income Tax Expense (Benefit)	(156.3)	26	287.6
Income Tax Expense	$ 317.2	$ 238.8	$ 171

Unrecognized tax benefits (Deta

Unrecognized tax benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax [Abstract]
Balance at Beginning of Year	$ 198.8	$ 219.7	$ 241
Decreases for Tax Positions Related to Prior Years	(21)	(20.9)	(21)
Lapse of the Applicable Statute of Limitations	(0.4)	0	(0.3)
Balance at End of Year	177.4	198.8	219.7
Less Tax Attributable to Temporary Items Included Above	(63.5)	(84.7)	(105.9)
Total Unrecognized Tax Benefits that if Recognized Would Affect the Effective Tax Rate	$ 113.9	$ 114.1	$ 113.8

Income Tax Additional Informati

Income Tax Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018
Federal Income Tax Note
Income Taxes Receivable, Net Operating Loss, CARES Act			$ 36.5
Less Tax Attributable to Temporary Items Included Above	$ (63.5)	$ (84.7)	(105.9)
Unrecognized Tax Benefits, Interest on Income Taxes Expense	7.8	5.5	7.8
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	34	26.2	20.6
Valuation Allowance on Deferred Tax Assets	10.3	12.7
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	2.4	1.8
Income Taxes Paid, Net	375	51	200
Tax Year 2017
Federal Income Tax Note
Increases for Tax Positions Related to Prior Years				$ 261.1
Foreign Tax Authority | Her Majesty's Revenue and Customs (HMRC)
Federal Income Tax Note
Tax Expense for Revaluation of Tax Assets and Liabilities due to Finance Bill 2019-21		$ 24.2	$ 9.3
State and Local Jurisdiction
Federal Income Tax Note
Operating Loss Carryforwards	$ 187.6

Debt Schedule (Detail)

Debt Schedule (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument
Long-term Debt, Excluding Current Maturities	$ 3,427.8	$ 3,442.2
Debt Instrument, Unamortized Premium (Discount), Net	2.5	2.3
Debt Issuance Costs, Noncurrent, Net	(33.2)	(34.6)
Long-term Debt	3,429.8	3,442.2
Five-Year Term Loan Facility
Debt Instrument
Line of Credit Facility, Fair Value of Amount Outstanding	350	0
Notes Issued in 1998 with 2028 Maturity Date | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	335.8	335.8
Notes Issued in 2002 | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	39.5	39.5
Notes Payable due 2042 | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	500	500
Notes Issued in 2014 | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	0	350
Notes Issued in 2015 | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	275	275
Notes Issued in 2019 | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	400	400
Notes Issued in 2019 due 2049 | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	450	450
Notes Issued in 2021 due 2051 | Senior Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	600	600
Notes Issued 1990 to 1996 | Medium-term Notes
Debt Instrument
Short-term Debt, outstanding principal	2	0
Notes Issued 1990 to 1996 | Medium-term Notes
Debt Instrument
Long-term Debt, Excluding Current Maturities	18.5	20.5
Notes Issued in 1998 with 2038 Maturity Date | Junior Subordinated Debt
Debt Instrument
Long-term Debt, Excluding Current Maturities	189.7	203.7
Notes Issued in 2018 with a 2058 Maturity Date | Junior Subordinated Debt
Debt Instrument
Long-term Debt, Excluding Current Maturities	$ 300	$ 300

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2007	Dec. 31, 1998	Dec. 31, 2019
Debt Additional Information
Repayments of Principal in 2023	$ 2
Repayments of Principal in 2025	275
Repayments of Principal in 2027	350
Repayments of Principal Thereafter	$ 2,833.5
Unum Group Percentage Ownership of Provident Financing Trust	100%
Derivative, Notional Amount	$ 1,753.9	$ 970.5
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	172.9	181.6	$ 178.1
Five-year Unsecured Revolving Credit Facility
Debt Additional Information
Letters of Credit Outstanding	0.4
Line of Credit Facility, Maximum Borrowing Capacity	500
Line of Credit Facility, Additional Borrowing Capacity If Requested	200
Parent Company | Five-year Unsecured Revolving Credit Facility
Debt Additional Information
Letters of Credit Outstanding	0
Parent Company | Facility agreement for contingent issuance of senior notes
Debt Additional Information
Line of Credit Facility, Maximum Borrowing Capacity	$ 400
Line of Credit Facility, Commitment Fee Percentage	2.225%
Debt Instrument, Covenant Description	2.0 billion
Notes Issued in 1998 with 2038 Maturity Date | Junior Subordinated Debt
Debt Additional Information
Stated Interest Rate of Debt					7.405%
Proceeds from Issuance of Senior Long-term Debt					$ 300
Liquidation value per capital security	$ 1,000
7.405% junior subordinated debt securities due 2038
Debt Additional Information
Debt Instrument, Repurchased Face Amount	$ 14
Costs Related to Early Retirement of Debt	1.2
Notes 5.625 Due 2020
Debt Additional Information
Debt Instrument, Repurchased Face Amount		400
4.500% Senior Notes due 2025
Debt Additional Information
Costs Related to Early Retirement of Debt	67.3
4.500% Senior Notes due 2025 | Senior Notes
Debt Additional Information
Proceeds from Issuance of Debt		500
Secured Notes Issued in 2007 | Senior Notes
Debt Additional Information
Extinguishment of Debt, Amount		$ 35
4.125% Senior Notes due 2051 | Senior Notes
Debt Additional Information
Proceeds from Issuance of Debt	$ 600
Stated Interest Rate of Debt	4.125%
4.000% Notes due 2024
Debt Additional Information
Stated Interest Rate of Debt	4%
Debt Instrument, Repurchased Face Amount	$ 350
Costs Related to Early Retirement of Debt	$ 3
Senior Notes | Notes 5.625 Due 2020
Debt Additional Information
Stated Interest Rate of Debt		5.625%
Senior Notes | 4.500% Senior Notes due 2025
Debt Additional Information
Stated Interest Rate of Debt		4.50%
Junior Subordinated Debt | Junior Subordinated Notes Payable Due 2038
Debt Additional Information
Stated Interest Rate of Debt					7.405%
Receive Fixed/Pay Variable | Interest Rate Swaps
Debt Additional Information
Notional Amount Of Derivatives Terminations			$ 250
Derivative, Notional Amount						$ 250
Northwind Holdings LLC
Debt Additional Information
Proceeds from Issuance of Senior Long-term Debt				$ 800
Periodic Principal Payments		$ 45
Basis Spread on LIBOR				0.78%

Employee Benefit Plans Change i

Employee Benefit Plans Change in Projected Benefit Obligation Amount (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Plan | UNITED STATES
Defined Benefit Plan, Change in Benefit Obligation
Benefit Obligation at Beginning of Year	$ 2,207.5	$ 2,277.2
Service Cost	7.7	9.6	$ 11
Interest Cost	67.2	65	73
Plan Participant Contributions	0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(604.1)	(57.9)
Benefits and Expenses Paid	(92.8)	(86.4)
Change in Foreign Exchange Rates	0	0
Benefit Obligation at End of Year	1,585.5	2,207.5	2,277.2
Defined Benefit Plan, Change in Fair Value of Plan Assets
Fair Value of Plan Assets at Beginning of Year	1,801.7	1,710.9
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	(410.6)	167.6
Employer Contributions to Defined Benefit Plan	10	9.6
Plan Participant Contributions	0	0
Benefits and Expenses Paid	(92.8)	(86.4)
Effect of Foreign Exchange Rates on Plan Assets	0	0
Fair Value of Plan Assets at End of Year	1,308.3	1,801.7	1,710.9
Accumulated Benefit Obligation	1,585.5	2,207.5
Funded Status of Plan	277.2	405.8
Pension Plan | UNITED KINGDOM
Defined Benefit Plan, Change in Benefit Obligation
Benefit Obligation at Beginning of Year	278.3	300
Service Cost	0	0	0
Interest Cost	5	4.2	4.9
Plan Participant Contributions	0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(92.4)	(18)
Benefits and Expenses Paid	(5.4)	(5.2)
Change in Foreign Exchange Rates	(27.6)	(2.7)
Benefit Obligation at End of Year	157.9	278.3	300
Defined Benefit Plan, Change in Fair Value of Plan Assets
Fair Value of Plan Assets at Beginning of Year	303.7	294.1
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	(128.4)	18
Employer Contributions to Defined Benefit Plan	0	0
Plan Participant Contributions	0	0
Benefits and Expenses Paid	(5.4)	(5.2)
Effect of Foreign Exchange Rates on Plan Assets	(29.4)	(3.2)
Fair Value of Plan Assets at End of Year	140.5	303.7	294.1
Accumulated Benefit Obligation	158	276.5
Funded Status of Plan	17.4	(25.4)
Other Postretirement Benefit Plans
Defined Benefit Plan, Change in Benefit Obligation
Benefit Obligation at Beginning of Year	110.3	120.5
Service Cost	0	0	0
Interest Cost	3	3	4.1
Plan Participant Contributions	0.1	0.1
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(19.4)	(3)
Benefits and Expenses Paid	(10.1)	(10.3)
Change in Foreign Exchange Rates	0	0
Benefit Obligation at End of Year	83.9	110.3	120.5
Defined Benefit Plan, Change in Fair Value of Plan Assets
Fair Value of Plan Assets at Beginning of Year	9	9.3
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0.1	0.1
Employer Contributions to Defined Benefit Plan	9.4	9.8
Plan Participant Contributions	0.1	0.1
Benefits and Expenses Paid	(10.1)	(10.3)
Effect of Foreign Exchange Rates on Plan Assets	0	0
Fair Value of Plan Assets at End of Year	8.5	9	$ 9.3
Funded Status of Plan	$ 75.4	$ 101.3

Employee Benefit Plans Amounts

Employee Benefit Plans Amounts Recognized in Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Current Pension Liability	$ 8.8	$ 8.4
Noncurrent Pension Liability	268.4	397.4
Noncurrent Pension Asset	0	0
Funded Status of Plan	277.2	405.8
Net Actuarial Gain (Loss) in Balance Sheet	(517.8)	(621.8)
Prior Service Credit in Balance Sheet	(0.6)	(0.6)
Pension Recognized in Balance Sheet, Gross of Deferred Tax	(518.4)	(622.4)
Pension Deferred Tax Asset in Balance Sheet	213.5	239.2
Pension Recognized in Balance Sheet, Net of Deferred Tax	(304.9)	(383.2)	$ (494.6)
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Current Pension Liability	0	0
Noncurrent Pension Liability	17.4	0
Noncurrent Pension Asset	0	(25.4)
Funded Status of Plan	17.4	(25.4)
Net Actuarial Gain (Loss) in Balance Sheet	(83.7)	(42.9)
Prior Service Credit in Balance Sheet	(0.2)	(0.2)
Pension Recognized in Balance Sheet, Gross of Deferred Tax	(83.9)	(43.1)
Pension Deferred Tax Asset in Balance Sheet	19.5	9.1
Pension Recognized in Balance Sheet, Net of Deferred Tax	(64.4)	(34)	(54.7)
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Current Pension Liability	1.1	1.4
Noncurrent Pension Liability	74.3	99.9
Noncurrent Pension Asset	0	0
Funded Status of Plan	75.4	101.3
Net Actuarial Gain (Loss) in Balance Sheet	31.6	13.6
Prior Service Credit in Balance Sheet	2.5	2.7
Pension Recognized in Balance Sheet, Gross of Deferred Tax	34.1	16.3
Pension Deferred Tax Asset in Balance Sheet	1.1	4.9
Pension Recognized in Balance Sheet, Net of Deferred Tax	$ 35.2	$ 21.2	$ 19.3

Employee Benefit Plans Amount_2

Employee Benefit Plans Amounts Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension Recognized in Balance Sheet, Net of Deferred Tax, Beginning of Year	$ (383.2)	$ (494.6)
Amortization of Net Actuarial Loss (Gain)	16.3	21.3	$ 18.7
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	87.7	124.8
Amortization of Prior Service Cost (Credit)	0	0	0.1
Change in Unrecognized Pension and Postretirement Benefit Costs, Tax Expense	(25.7)	(34.7)
Pension Recognized in Balance Sheet, Net of Deferred Tax, End of Year	(304.9)	(383.2)	(494.6)
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension Recognized in Balance Sheet, Net of Deferred Tax, Beginning of Year	(34)	(54.7)
Amortization of Net Actuarial Loss (Gain)	0.4	1.3	1.1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	(41.2)	26.3
Amortization of Prior Service Cost (Credit)	0	0	0
Change in Unrecognized Pension and Postretirement Benefit Costs, Tax Expense	10.4	(6.9)
Pension Recognized in Balance Sheet, Net of Deferred Tax, End of Year	(64.4)	(34)	(54.7)
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension Recognized in Balance Sheet, Net of Deferred Tax, Beginning of Year	21.2	19.3
Amortization of Net Actuarial Loss (Gain)	(1)	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	19	2.6
Amortization of Prior Service Cost (Credit)	(0.2)	(0.2)	(0.2)
Change in Unrecognized Pension and Postretirement Benefit Costs, Tax Expense	(3.8)	(0.5)
Pension Recognized in Balance Sheet, Net of Deferred Tax, End of Year	$ 35.2	$ 21.2	$ 19.3

Employee Benefit Plans US Pensi

Employee Benefit Plans US Pension Assets, Fair Value Measurement by Input Level (Details) - UNITED STATES - Pension Plan - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
U.S. Large Cap
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		$ 144.9
U.S. Large Cap | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
U.S. Large Cap | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
U.S. Large Cap | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
U.S. Large Cap | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		144.9
U.S. Small Cap
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		63.3
U.S. Small Cap | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		32.8
U.S. Small Cap | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
U.S. Small Cap | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
U.S. Small Cap | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		30.5
Global
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	$ 463.1	388.7
Global | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	57.4	0
Global | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Global | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Global | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	405.7	388.7
Emerging Markets
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		59.8
Emerging Markets | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
Emerging Markets | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
Emerging Markets | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		0
Emerging Markets | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount		59.8
U.S. Government and Agencies
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	215.7	419.3
U.S. Government and Agencies | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	194	419.3
U.S. Government and Agencies | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	21.7	0
U.S. Government and Agencies | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
U.S. Government and Agencies | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Corporate
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	129.6	103.3
Corporate | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Corporate | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Corporate | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Corporate | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	129.6	103.3
Foreign Emerging Market Fixed Income Securities
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	54
Foreign Emerging Market Fixed Income Securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0
Foreign Emerging Market Fixed Income Securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0
Foreign Emerging Market Fixed Income Securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0
Foreign Emerging Market Fixed Income Securities | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	54
Opportunistic Credits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	132.3	212.5
Opportunistic Credits | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Opportunistic Credits | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Opportunistic Credits | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Opportunistic Credits | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	132.3	212.5
Real Estate
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	164.2	247.1
Real Estate | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Real Estate | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Real Estate | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Real Estate | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	164.2	247.1
Private Equity Direct Investments
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	74.5	80.4
Private Equity Direct Investments | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Private Equity Direct Investments | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Private Equity Direct Investments | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Private Equity Direct Investments | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	74.5	80.4
Private Equity Funds of Funds
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	47.6	50.5
Private Equity Funds of Funds | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Private Equity Funds of Funds | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Private Equity Funds of Funds | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Private Equity Funds of Funds | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	47.6	50.5
Cash Equivalents
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	20.5	31.9
Cash Equivalents | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	20.5	31.9
Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Cash Equivalents | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Cash Equivalents | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Total Invested Assets
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1,301.5	1,801.7
Total Invested Assets | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	271.9	484
Total Invested Assets | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	21.7	0
Total Invested Assets | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Total Invested Assets | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	$ 1,007.9	$ 1,317.7

Employee Benefit Plans UK Pensi

Employee Benefit Plans UK Pension Assets, Fair Value Measurement by Input Level (Details) - Pension Plan - UNITED KINGDOM - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Diversified Growth Assets
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	$ 40.6	$ 157.3
Diversified Growth Assets | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	32.3	113.1
Diversified Growth Assets | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Diversified Growth Assets | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Diversified Growth Assets | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	8.3	44.2
Fixed Income and Index-linked Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	70.6	124.1
Fixed Income and Index-linked Securities | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	70.6	124.1
Fixed Income and Index-linked Securities | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fixed Income and Index-linked Securities | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Fixed Income and Index-linked Securities | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Alternative Investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	28.1	18.2
Alternative Investments | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Alternative Investments | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Alternative Investments | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Alternative Investments | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	28.1	18.2
Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1.9	4.1
Cash Equivalents | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	1.9	4.1
Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Cash Equivalents | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Cash Equivalents | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Total Invested Assets
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	141.2	303.7
Total Invested Assets | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	104.8	241.3
Total Invested Assets | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Total Invested Assets | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	0	0
Total Invested Assets | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount	$ 36.4	$ 62.4

Employee Benefit Plans OPEB Pla

Employee Benefit Plans OPEB Plan Assets, Fair Value Measurements by Input Level (Details) - Other Postretirement Benefit Plans - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans
Life Settlement Contracts, Fair Value Method, Face Value	$ 8.5	$ 9
Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Life Settlement Contracts, Fair Value Method, Face Value	0	0
Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Life Settlement Contracts, Fair Value Method, Face Value	0	0
Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Life Settlement Contracts, Fair Value Method, Face Value	$ 8.5	$ 9

Employee Benefit Plans OPEB Cha

Employee Benefit Plans OPEB Changes in Assets Measured at Fair Value Using Signficant Unobservable Inputs (Details) - Other Postretirement Benefit Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Fair Value of Plan Assets at Beginning of Year	$ 9	$ 9.3
Fair Value of Plan Assets at End of Year	8.5	9
Fair Value, Inputs, Level 3 | Life Insurance Contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Fair Value of Plan Assets at Beginning of Year	9	9.3
Actual Return on Plan Assets Still Held	0.1	0.1
Plan Participant Contributions	9.5	9.9
Defined Benefit Plan, Plan Assets, Benefits Paid	10.1	10.3
Fair Value of Plan Assets at End of Year	$ 8.5	$ 9

Employee Benefit Plans Measurem

Employee Benefit Plans Measurement Assumptions (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Discount Rate Assumptions Used Calculating Benefit Obligation	5.70%	3.10%
Discount Rate Assumptions Used Calculating Net Periodic Benefit Cost	3.10%	2.90%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	6%	6%
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Discount Rate Assumptions Used Calculating Benefit Obligation	4.80%	2%
Rate of Compensation Increase Assumptions Used Calculating Benefit Obligation	2.50%	2.90%
Discount Rate Assumptions Used Calculating Net Periodic Benefit Cost	2%	1.40%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	4.20%	3.50%
Rate of Compensation Increase Assumptions Used Calculating Net Periodic Benefit Cost	2.90%	2.80%
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Discount Rate Assumptions Used Calculating Benefit Obligation	5.70%	2.90%
Discount Rate Assumptions Used Calculating Net Periodic Benefit Cost	2.90%	2.60%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	5.75%	5.75%

Employee Benefit Plans Net Peri

Employee Benefit Plans Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	$ 7.7	$ 9.6	$ 11
Interest Cost	67.2	65	73
Expected Return on Plan Assets	(105.9)	(100.6)	(106.7)
Amortization of Net Actuarial Loss (Gain)	16.3	21.3	18.7
Amortization of Prior Service Cost (Credit)	0	0	0.1
Curtailment Gain	0	0	0
Net Periodic Benefit Cost	(14.7)	(4.7)	(3.9)
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0	0	0
Interest Cost	5	4.2	4.9
Expected Return on Plan Assets	(10.9)	(9.8)	(9.5)
Amortization of Net Actuarial Loss (Gain)	0.4	1.3	1.1
Amortization of Prior Service Cost (Credit)	0	0	0
Curtailment Gain	0	0	0.1
Net Periodic Benefit Cost	(5.5)	(4.3)	(3.4)
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0	0	0
Interest Cost	3	3	4.1
Expected Return on Plan Assets	(0.5)	(0.5)	(0.5)
Amortization of Net Actuarial Loss (Gain)	(1)	0	0
Amortization of Prior Service Cost (Credit)	(0.2)	(0.2)	(0.2)
Curtailment Gain	0	0	0
Net Periodic Benefit Cost	$ 1.3	$ 2.3	$ 3.4

Employee Benefit Plans Expected

Employee Benefit Plans Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2022 USD ($)
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Benefit Payments in Year One	$ 84.9
Benefit Payments in Year Two	88.2
Benefit Payments in Year Three	92.1
Benefit Payments in Year Four	96.5
Benefit Payments in Year Five	100.6
Benefit Payments in Five Fiscal Years Thereafter	550.6
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Benefit Payments in Year One	5.4
Benefit Payments in Year Two	5.5
Benefit Payments in Year Three	5.7
Benefit Payments in Year Four	5.8
Benefit Payments in Year Five	6
Benefit Payments in Five Fiscal Years Thereafter	32.4
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Benefit Payments in Year One	10
Prescription Drug Subsidy Receipts in Year One	0.1
Net OPEB Payments in Year One	9.9
Benefit Payments in Year Two	9.4
Prescription Drug Subsidy Receipts in Year Two	0.1
Net OPEB Payments in Year Two	9.3
Benefit Payments in Year Three	9
Prescription Drug Subsidy Receipts in Year Three	0.1
Net OPEB Payments in Year Three	8.9
Benefit Payments in Year Four	8.5
Prescription Drug Subsidy Receipts in Year Four	0
Net OPEB Payments in Year Four	8.5
Benefit Payments in Year Five	8.1
Prescription Drug Subsidy Receipts in Year Five	0
Net OPEB Payments in Year Five	8.1
Benefit Payments in Five Fiscal Years Thereafter	34
Prescription Drug Subsidy Receipts in Five Fiscal Years Thereafter	0.1
Net OPEB Payments in Five Fiscal Years Thereafter	$ 33.9

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension and Other Postretirement Benefits Disclosure
Health Care Cost Trend Rate Assumed for Next Fiscal Year	7%	6.25%
Ultimate Health Care Cost Trend Rate	5%
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate	2031
Pension Plan | UNITED STATES
Pension and Other Postretirement Benefits Disclosure
Average Remaining Life Expectancy of Plan Participants	24 years
Alternative Investments, Unfunded Commitments	$ 24.5	$ 28.5
Pension Plan | UNITED KINGDOM
Pension and Other Postretirement Benefits Disclosure
Average Remaining Life Expectancy of Plan Participants	28 years
Alternative Investments, Unfunded Commitments	$ 17.3	28.1
Other Postretirement Benefit Plans
Pension and Other Postretirement Benefits Disclosure
Average Remaining Expected Working Life of Plan Participants	2 years
Investment Level 3 Transfers Into	$ 0	0
Investment Level 3 Transfers Out of	$ 0	$ 0
Interest Rate During Period	4.31%	4.59%
Other Postretirement Benefit Plans | UNITED STATES
Pension and Other Postretirement Benefits Disclosure
Matching Contribution Percent of Employees' Gross Pay	5%
Employer Discretionary Contribution Percentage of earnings	4.50%
Cost Recognized	$ 70.9	$ 71	$ 83.4
Other Postretirement Benefit Plans | UNITED KINGDOM
Pension and Other Postretirement Benefits Disclosure
Defined Contribution Plan, Minimum Employee Contribution Eligible for Matching	1%
Defined Contribution Plan, Maximum Employee Contribution Eligible for Matching	5%
Cost Recognized	$ 4.9	$ 4.9	$ 5
Equity Securities | Pension Plan | UNITED STATES
Pension and Other Postretirement Benefits Disclosure
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	38%
Fixed Maturity Securities | Pension Plan | UNITED STATES
Pension and Other Postretirement Benefits Disclosure
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	30%
Diversified Growth Assets | Pension Plan | UNITED KINGDOM
Pension and Other Postretirement Benefits Disclosure
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50%
Alternative Investments | Pension Plan | UNITED STATES
Pension and Other Postretirement Benefits Disclosure
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	32%
Fixed Income and Index-linked Securities | Pension Plan | UNITED KINGDOM
Pension and Other Postretirement Benefits Disclosure
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50%
Minimum | Other Postretirement Benefit Plans | UNITED KINGDOM
Pension and Other Postretirement Benefits Disclosure
Matching Contribution Percent of Employees' Gross Pay	8%
Minimum | Private Equity Funds of Funds | Pension Plan | UNITED STATES
Pension and Other Postretirement Benefits Disclosure
Private Equity Partnership Future Liquidation Term	5 years
Maximum | Other Postretirement Benefit Plans | UNITED KINGDOM
Pension and Other Postretirement Benefits Disclosure
Matching Contribution Percent of Employees' Gross Pay	12%
Maximum | Private Equity Funds of Funds | Pension Plan | UNITED STATES
Pension and Other Postretirement Benefits Disclosure
Private Equity Partnership Future Liquidation Term	8 years

Basic and Diluted Earnings Per

Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator
Net Income	$ 1,314.2	$ 824.2	$ 793
Denominator
Weighted Average Common Shares - Basic	200,647,200	204,232,900	203,642,000
Dilution for Assumed Exercises of Stock Options and Nonvested Stock Awards	1,462,200	615,000	113,300
Weighted Average Common Shares - Assuming Dilution	202,109,400	204,847,900	203,755,300
Net Income Per Common Share
Basic	$ 6.55	$ 4.04	$ 3.89
Assuming Dilution	$ 6.50	$ 4.02	$ 3.89

Treasury Stock Transactions (De

Treasury Stock Transactions (Details) - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Class of Stock Disclosures [Abstract]
Number of Treasury Shares Repurchased		5.7	1.9	0
Cost of Shares Repurchased	[1]	$ 200.1	$ 50	$ 0
Commission Paid on Stock Repurchases		$ 0.1
[1]Includes commissions of $0.1 million for the year ended December 31, 2022.

Stockholders' Equity and Earn_3

Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Feb. 21, 2023	Dec. 01, 2022	Oct. 25, 2021
Stockholders Equity and Earnings Per Common Share Additional Information [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share		100,000	1,100,000	1,600,000
Cost of Shares Repurchased	[1]	$ 200.1	$ 50	$ 0
Number of Treasury Shares Repurchased		5,700,000	1,900,000	0
Authorized Shares of Preferred Stock		25,000,000
Par Value Per Share of Preferred Stock		$ 0.10
Issued Shares of Preferred Stock		0
Accelerated Share Repurchase Agreement [Member]
Stockholders Equity and Earnings Per Common Share Additional Information [Line Items]
Cost of Shares Repurchased		$ 50	$ 50
Number of Treasury Shares Repurchased		1,700,000	1,900,000
Open Market Share Repurchases [Member]
Stockholders Equity and Earnings Per Common Share Additional Information [Line Items]
Cost of Shares Repurchased		$ 150.1
Number of Treasury Shares Repurchased		4,000,000	0
Repurchase Program Authorized in October 2021 [Member]
Stockholders Equity and Earnings Per Common Share Additional Information [Line Items]
Authorized Amount of Treasury Share Repurchases Under Stock Repurchase Program							$ 250
Remaining Amount of Treasury Share Repurchases Authorized Under Stock Repurchase Program		$ 0
Repurchase Program Authorized in December 2022 [Member]
Stockholders Equity and Earnings Per Common Share Additional Information [Line Items]
Authorized Amount of Treasury Share Repurchases Under Stock Repurchase Program						$ 200
Repurchase Program Authorized in February 2023 [Member] | Subsequent Event
Stockholders Equity and Earnings Per Common Share Additional Information [Line Items]
Authorized Amount of Treasury Share Repurchases Under Stock Repurchase Program					$ 250
[1]Includes commissions of $0.1 million for the year ended December 31, 2022.

Stock-Based Compensation - Valu

Stock-Based Compensation - Valuation Assumptions on PSU Grants (Details) - Performance Share Units	12 Months Ended
	Dec. 31, 2020 Rate
Share-based Compensation Arrangement by Share-based Payment Award
Expected Volatility Rate	23%
Expected Life	3 years
Risk Free Interest Rate	0.85%

Stock-Based Compensation - Acti

Stock-Based Compensation - Activity for CIUs (Details) - Cash Incentive Units (CIUs) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Liability Instruments, Nonvested, Number of Shares
Shares Outstanding Beginning Balance	7,223
Shares Granted	8,024
Shares Outstanding Ending Balance	15,247	7,223
Weighted Average Grant Date Fair Value at Beginning of Period	$ 1.07
Weighted Average Grant Date Fair Value of Shares Granted	1.09	$ 1.07
Weighted Average Grant Date Fair Value at End of Period	$ 1.08	$ 1.07

Stock-Based Compensation - Va_2

Stock-Based Compensation - Valuation Assumptions on CIU Grants (Details) - Cash Incentive Units (CIUs)	12 Months Ended
	Dec. 31, 2022 Rate	Dec. 31, 2021 Rate
Share-based Compensation Arrangement by Share-based Payment Award
Expected Volatility Rate	30%	50%
Expected Life	3 years	3 years
Risk Free Interest Rate	4.26%	0.71%

Stock-Based Compensation - Nonv

Stock-Based Compensation - Nonvested Stock Awards Classified in Equity (Details) - Restricted Stock Units (RSUs) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares
Shares Outstanding Beginning Balance	2,016
Shares Granted	1,323
Shares Vested	(1,018)
Shares Forfeited	(139)
Shares Outstanding Ending Balance	2,182	2,016
Weighted Average Grant Date Fair Value at Beginning of Period	$ 26.63
Weighted Average Grant Date Fair Value of Shares Granted	28.21	$ 27.02	$ 22.71
Weighted Average Grant Date Fair Value of Shares Vested	27.51
Weighted Average Grant Date Fair Value of Shares Forfeited	26.19
Weighted Average Grant Date Fair Value at End of Period	$ 27.20	$ 26.63

Stock-Based Compensation - Ac_2

Stock-Based Compensation - Activity for Cash-Settled RSUs (Details) - Cash Settled RSUs shares in Thousands	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Liability Instruments, Nonvested, Number of Shares
Shares Outstanding Beginning Balance | shares	46
Shares Vested | shares	(23)
Shares Outstanding Ending Balance | shares	23
Weighted Average Grant Date Fair Value at Beginning of Period | $ / shares	$ 23.31
Weighted Average Grant Date Fair Value of Shares Vested | $ / shares	23.31
Weighted Average Grant Date Fair Value at End of Period | $ / shares	$ 23.31

Stock-Based Compensation Expens

Stock-Based Compensation Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense, Before Tax	$ 52,700,000	$ 35,400,000	$ 30,400,000
Allocated Share-based Compensation Expense, Net of Tax	47,300,000	31,100,000	26,100,000
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense, Before Tax	5,700,000	3,300,000	5,600,000
Cash Incentive Units (CIUs)
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense, Before Tax	12,800,000	3,200,000	0
Restricted Stock Units and Cash-Settled Awards
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense, Before Tax	32,700,000	25,500,000	23,900,000
Stock Success Units (SSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense, Before Tax	900,000	2,800,000	400,000
Other Awards
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense, Before Tax	$ 600,000	$ 600,000	$ 500,000

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Fair Value of Options Vested	$ 0	$ 0	$ 0
Intrinsic Value of Options Exercised	0	0.1	0.1
Cash Received Under Share-based Payment Arrangements	$ 4.2	$ 3.8	$ 4.4
Stock Incentive Plan 2017
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares Authorized	17,000,000
Number of Shares for Each Full Value Award	1.76
Total Duration of the Stock Incentive Plan	8 years
Award Vesting Period	3 years
Stock Incentive Plan 2022
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares Authorized	6,800,000
Number of Shares for Each Full Value Award	1
Total Duration of the Stock Incentive Plan	10 years
Number of Shares Available for Grant	6,600,000
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Weighted Average Grant Date Fair Value of Shares Granted	$ 40.67		$ 23.49
Shares Outstanding	0	308,000
Shares Granted	(75,000)
Award Vesting Period	3 years
Shares Forfeited	(2,000)
Shares Vested	(256,000)
Fair Value of Awards Vested During the Period	$ 4.2	$ 6.6	$ 6.5
Compensation Cost Not yet Recognized	$ 0
Weighted Average Grant Date Fair Value		$ 23.58
Weighted Average Grant Date Fair Value of Shares Vested	$ 16.29
Weighted Average Grant Date Fair Value of Shares Forfeited	23.58
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Weighted Average Grant Date Fair Value of Shares Granted	$ 28.21	$ 27.02	$ 22.71
Shares Outstanding	2,182,000	2,016,000
Shares Granted	1,323,000
Shares Forfeited	(139,000)
Shares Vested	(1,018,000)
Fair Value of Awards Vested During the Period	$ 28	$ 23.9	$ 25.1
Compensation Cost Not yet Recognized	$ 31.9
Period for Recognition of Compensation Cost Not Yet Recognized	9 months 18 days
Weighted Average Grant Date Fair Value	$ 27.20	$ 26.63
Weighted Average Grant Date Fair Value of Shares Vested	27.51
Weighted Average Grant Date Fair Value of Shares Forfeited	$ 26.19
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Stock Option Compensation Not yet Recognized	$ 0
Shares Exercisable	0
Stock Success Units (SSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Weighted Average Grant Date Fair Value of Shares Granted	$ 18.78	$ 18.78	$ 18.78
Shares Outstanding	208,000	208,000
Shares Granted	0	0
Award Vesting Period	6 years
Shares Forfeited	0
Shares Vested	0		0
Fair Value of Awards Vested During the Period		$ 1.9
Compensation Cost Not yet Recognized	$ 1.7
Period for Recognition of Compensation Cost Not Yet Recognized	1 year 2 months 12 days
Cash Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Compensation Cost Not yet Recognized	$ 0.2
Period for Recognition of Compensation Cost Not Yet Recognized	1 month 6 days
Weighted Average Grant Date Fair Value of Shares Granted	$ 0	$ 22.94
Share-Based Compensation Arrangement by Share-Based Payment Award, Liability Instruments, Vested in Period, Fair Value	$ 0.7	$ 0.6
Cash Incentive Units (CIUs)
Share-based Compensation Arrangement by Share-based Payment Award
Award Vesting Period	3 years
Compensation Cost Not yet Recognized	$ 9.6
Period for Recognition of Compensation Cost Not Yet Recognized	1 year
Weighted Average Grant Date Fair Value of Shares Granted	$ 1.09	$ 1.07
Shares Granted	8,024,000
Minimum | Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of Stock-based Awards Possible to be Earned	40%
Minimum | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Award Vesting Period	1 year
Minimum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Award Vesting Period	1 year
Minimum | Cash Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Award Vesting Period	1 year
Minimum | Cash Incentive Units (CIUs)
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of Stock-based Awards Possible to be Earned	0%
Maximum | Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of Stock-based Awards Possible to be Earned	180%
Maximum | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Award Vesting Period	3 years
Maximum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Award Vesting Period	3 years
Maximum | Cash Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Award Vesting Period	3 years
Maximum | Cash Incentive Units (CIUs)
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of Stock-based Awards Possible to be Earned	200%

Reinsurance - Premium Income Da

Reinsurance - Premium Income Data (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reinsurance Disclosures [Abstract]
Direct Premium Income	$ 9,900.5	$ 9,742.8	$ 9,621.9
Reinsurance Assumed	78.7	90.6	94.1
Reinsurance Ceded	(355.8)	(352.4)	(337.9)
Premium Income	9,623.4	9,481	9,378.1
Ceded Benefits and Change in Reserves for Future Benefits	$ 1,034.6	$ 862.5	$ 628.8

Reinsurance - Additional Inform

Reinsurance - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($)	Dec. 16, 2020 USD ($)	Dec. 31, 2019 USD ($)
Negative Ceding Commission		$ 18.2	$ 437.7
Net Realized Gain Related to the Transfer of Investments	$ (15.7)	76.7	1,199.1
Transaction Costs Related to Reinsurance Transaction	1,020.2	1,008.6	996.6
Reinsurance Recoverables, Incurred but Not Reported Claims	8,279.8	8,697.8	8,378.9			$ 2,246.8
Prepaid Reinsurance Premiums	$ 713.3	777.1
Income Taxes Receivable, Net Operating Loss, CARES Act			36.5
Number of companies that make up majority of reinsurance recoverable	9
Closed Block Individual Disability Reinsurance Transaction
Net Realized Gain Related to the Transfer of Investments		67.6	1,302.3
Increase in Benefits and Change in Reserves for Future Benefits		133.1	1,284.5
Transaction Costs Related to Reinsurance Transaction		6.2	21
Reinsurance Recoverables, Incurred but Not Reported Claims				$ 990	$ 6,141.5
Prepaid Reinsurance Premiums				43.1	815.7
Deposit Contracts, Assets				$ 5	$ 88.2
Amortization of Prepaid Reinsurance Premium	$ 63.8	$ 79.1	$ 2.6
AM Best A Rating or Better | Reinsurer Concentration Risk | Reinsurance Recoverable | Commonwealth Annuity and Life Insurance Company
Percentage of Concentration Risk	59%
AM Best A Rating or Better | Reinsurer Concentration Risk | Reinsurance Recoverable | Top 9 Reinsurers
Percentage of Concentration Risk	36%
AM Best, A- Rating | Reinsurer Concentration Risk | Reinsurance Recoverable | Other Reinsurers
Percentage of Concentration Risk	4%
AM Best, Below A- or Not Rated | Reinsurer Concentration Risk | Reinsurance Recoverable | Other Reinsurers
Percentage of Concentration Risk	1%

Premium Income by Major Line of

Premium Income by Major Line of Business within Each Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information
Premium Income	$ 9,623.4	$ 9,481	$ 9,378.1
Accident, Sickness, and Disability
Segment Reporting Information
Premium Income	7,060.8	7,072.9	6,975.2
Life
Segment Reporting Information
Premium Income	2,562.6	2,408.1	2,402.9
Operating Segments
Segment Reporting Information
Premium Income	9,623.4	9,481	9,378.1
Operating Segments | Unum US
Segment Reporting Information
Premium Income	6,258.3	6,078	6,018.9
Operating Segments | Unum US | Group Long-term Disability
Segment Reporting Information
Premium Income	1,911.7	1,827.8	1,828.5
Operating Segments | Unum US | Group Short-term Disability
Segment Reporting Information
Premium Income	926.3	864	799.2
Operating Segments | Unum US | Group Life
Segment Reporting Information
Premium Income	1,669.1	1,641.9	1,640.5
Operating Segments | Unum US | Accidental Death & Dismemberment
Segment Reporting Information
Premium Income	173.7	165.1	163.9
Operating Segments | Unum US | Voluntary Benefits
Segment Reporting Information
Premium Income	840.6	846.7	875.2
Operating Segments | Unum US | Individual Disability
Segment Reporting Information
Premium Income	461.1	459.8	456
Operating Segments | Unum US | Dental and Vision
Segment Reporting Information
Premium Income	275.8	272.7	255.6
Operating Segments | Unum International
Segment Reporting Information
Premium Income	718.8	717	652.8
Operating Segments | Unum International | Group Long-term Disability
Segment Reporting Information
Premium Income	376.9	401.9	364.9
Operating Segments | Unum International | Group Life
Segment Reporting Information
Premium Income	138.2	112.3	108.5
Operating Segments | Unum International | Supplemental
Segment Reporting Information
Premium Income	114	112.6	99.8
Operating Segments | Unum International | Unum Poland
Segment Reporting Information
Premium Income	89.7	90.2	79.6
Operating Segments | Colonial Life
Segment Reporting Information
Premium Income	1,702	1,690.2	1,712
Operating Segments | Colonial Life | Accident, Sickness, and Disability
Segment Reporting Information
Premium Income	948.9	953.3	975.1
Operating Segments | Colonial Life | Life
Segment Reporting Information
Premium Income	401.1	384.7	376.4
Operating Segments | Colonial Life | Cancer and Critical Illness Colonial
Segment Reporting Information
Premium Income	352	352.2	360.5
Operating Segments | Closed Block
Segment Reporting Information
Premium Income	944.3	995.8	994.4
Operating Segments | Closed Block | Long-term Care
Segment Reporting Information
Premium Income	697.4	704.3	666.9
Operating Segments | Closed Block | Other Insurance Product Line
Segment Reporting Information
Premium Income	$ 246.9	$ 291.5	$ 327.5

Selected Operating Statement Da

Selected Operating Statement Data by Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information
Premium Income	$ 9,623.4	$ 9,481	$ 9,378.1
Net Investment Income	2,122.2	2,213.2	2,360.7
Other Income	261.1	242.9	224.2
Interest and Debt Expense	188.5	185	188.2
Operating Segments
Segment Reporting Information
Premium Income	9,623.4	9,481	9,378.1
Net Investment Income	2,122.2	2,213.2	2,360.7
Other Income	261.1	242.9	224.2
Adjusted Operating Revenue	12,006.7	11,937.1	11,963
Adjusted Operating Income (Loss)	1,555.9	1,116.6	1,278
Interest and Debt Expense	192.7	185	188.2
Depreciation and Amortization	701.4	703.1	722.3
Operating Segments | Unum US
Segment Reporting Information
Premium Income	6,258.3	6,078	6,018.9
Other Income	196.3	170	154.9
Adjusted Operating Revenue	7,130.9	6,969.6	6,894.1
Adjusted Operating Income (Loss)	970.7	464.9	825.4
Interest and Debt Expense	0	0	0
Depreciation and Amortization	370.6	400.9	421.7
Operating Segments | Unum International
Segment Reporting Information
Premium Income	718.8	717	652.8
Net Investment Income	170.1
Other Income	0.9	0.6	0.5
Adjusted Operating Revenue	889.8	850.3	757.9
Adjusted Operating Income (Loss)	127	105.7	76.6
Interest and Debt Expense	0	0	0
Depreciation and Amortization	22	21	20.1
Operating Segments | Colonial Life
Segment Reporting Information
Premium Income	1,702	1,690.2	1,712
Other Income	1.1	1	1.1
Adjusted Operating Revenue	1,855.8	1,863.2	1,868.8
Adjusted Operating Income (Loss)	374.6	329.2	335.4
Interest and Debt Expense	0	0	0
Depreciation and Amortization	303.5	275.4	273.9
Operating Segments | Closed Block
Segment Reporting Information
Premium Income	944.3	995.8	994.4
Other Income	58	65.1	66.6
Adjusted Operating Revenue	2,072.9	2,219.9	2,431.3
Adjusted Operating Income (Loss)	247.9	394.7	241.4
Interest and Debt Expense	0	0	3.1
Depreciation and Amortization	4.7	5.1	5.9
Operating Segments | Corporate and Other Segment
Segment Reporting Information
Premium Income	0	0	0
Other Income	4.8	6.2	1.1
Adjusted Operating Revenue	57.3	34.1	10.9
Adjusted Operating Income (Loss)	(164.3)	(177.9)	(200.8)
Interest and Debt Expense	192.7	185	185.1
Depreciation and Amortization	$ 0.6	$ 0.7	$ 0.7

Segment Information Deferred Ac

Segment Information Deferred Acquisition Costs by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year	$ 2,207.9
Deferred Policy Acquisition Costs, Amortization Expense	(591)	$ (586.1)	$ (606.1)
Deferred Acquisition Costs at End of Year	2,252.3	2,207.9
Operating Segments
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year	2,207.9	2,272.6	2,324
Deferral of Acquisition Costs	556.9	508.1	576.2
Deferred Policy Acquisition Costs, Amortization Expense	(591)	(586.1)	(606.1)
Adjustment Related to Unrealized Investment Gains and Losses	81.7	14.7	(22.4)
Deferred Policy Acquisition Costs Foreign Currency Translation Adjustment And Other	(3.2)	(1.4)	0.9
Deferred Acquisition Costs at End of Year	2,252.3	2,207.9	2,272.6
Operating Segments | Unum US
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year	1,096.2	1,168.7	1,223
Deferral of Acquisition Costs	273.1	242.7	291.5
Deferred Policy Acquisition Costs, Amortization Expense	(294.9)	(319)	(341)
Adjustment Related to Unrealized Investment Gains and Losses	15	3.8	(4.8)
Deferred Policy Acquisition Costs Foreign Currency Translation Adjustment And Other	0	0	0
Deferred Acquisition Costs at End of Year	1,089.4	1,096.2	1,168.7
Operating Segments | Unum International
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year	35.4	32	26.4
Deferral of Acquisition Costs	12	12.8	12.1
Deferred Policy Acquisition Costs, Amortization Expense	(7.6)	(8)	(7.4)
Adjustment Related to Unrealized Investment Gains and Losses	0	0	0
Deferred Policy Acquisition Costs Foreign Currency Translation Adjustment And Other	(3.2)	(1.4)	0.9
Deferred Acquisition Costs at End of Year	36.6	35.4	32
Operating Segments | Colonial Life
Movement Analysis of Deferred Policy Acquisition Costs
Deferred Acquisition Costs at Beginning of Year	1,076.3	1,071.9	1,074.6
Deferral of Acquisition Costs	271.8	252.6	272.6
Deferred Policy Acquisition Costs, Amortization Expense	(288.5)	(259.1)	(257.7)
Adjustment Related to Unrealized Investment Gains and Losses	66.7	10.9	(17.6)
Deferred Policy Acquisition Costs Foreign Currency Translation Adjustment And Other	0	0	0
Deferred Acquisition Costs at End of Year	$ 1,126.3	$ 1,076.3	$ 1,071.9

Assets by Segment (Detail)

Assets by Segment (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information
Total Assets	$ 61,434.9	$ 70,115.6
Operating Segments | Unum US
Segment Reporting Information
Total Assets	16,278.7	18,696.3
Operating Segments | Unum International
Segment Reporting Information
Total Assets	3,154.9	4,086.5
Operating Segments | Colonial Life
Segment Reporting Information
Total Assets	4,448.9	4,895.9
Operating Segments | Closed Block
Segment Reporting Information
Total Assets	34,241.2	38,287.9
Operating Segments | Corporate and Other Segment
Segment Reporting Information
Total Assets	$ 3,311.2	$ 4,149

Reconciliation of Total Revenue

Reconciliation of Total Revenue and Income Before Income Tax to Operating Revenue and Operating Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting, Revenue Reconciling Item
Total Revenue	$ 11,991	$ 12,013.8	$ 13,162.1
Net Investment Gain (Loss)	(15.7)	76.7	1,199.1
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	1,631.4	1,063	964
Operating Lease, Impairment Loss		(13.9)	(12.7)
Closed Block Individual Disability Reinsurance Transaction
Segment Reporting, Revenue Reconciling Item
Net Investment Gain (Loss)		67.6	1,302.3
Amortization of the Cost of Reinsurance	(63.8)	(79.1)	(2.6)
Operating Segments
Segment Reporting, Revenue Reconciling Item
Total Revenue	11,991	12,013.8	13,162.1
Net Investment Gain (Loss)	(15.7)	76.7	1,199.1
Adjusted Operating Revenue	12,006.7	11,937.1	11,963
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	1,631.4	1,063	964
Net Reserve Decrease Related to Reserve Assumption Updates, Before Tax	155	181.4	(169)
Capitalized Computer Software, Impairments	0	(12.1)	0
Costs Related to Early Retirement of Debt	0	(67.3)	0
Operating Lease, Impairment Loss	0	(13.9)	(12.7)
Costs Related to Organizational Design Update			(23.3)
Adjusted Operating Income	1,555.9	1,116.6	1,278
Operating Segments | Closed Block Individual Disability Reinsurance Transaction
Segment Reporting, Revenue Reconciling Item
Net Investment Gain (Loss)	0	67.6	1,302.3
Change in Benefit Reserves and Transaction Costs	0	139.3	1,305.5
Amortization of the Cost of Reinsurance	(63.8)	(79.1)	(2.6)
Operating Segments | Unrelated to Significant Transaction
Segment Reporting, Revenue Reconciling Item
Net Investment Gain (Loss)	$ (15.7)	$ 9.1	$ (103.2)

Segment Information Segments -

Segment Information Segments - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) Integer	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting [Abstract]
Number of Operating Segments | Integer	3
Supplementary Insurance Information, by Segment
Goodwill	$ 347.6	$ 352.2
Operating Segments
Supplementary Insurance Information, by Segment
Capitalized Computer Software, Impairments	0	12.1	$ 0
Costs Related to Organizational Design Update			$ (23.3)
Unum US
Supplementary Insurance Information, by Segment
Goodwill	280	280
Unum International
Supplementary Insurance Information, by Segment
Goodwill	39.9	44.5
Colonial Life
Supplementary Insurance Information, by Segment
Goodwill	$ 27.7	$ 27.7

Leases, Cost (Details)

Leases, Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating Lease Cost	$ 19.6	$ 35.2	$ 48.6
Sublease Income	1.1	1	1.3
Total Lease Cost	18.5	34.2	47.3
Cash Paid for Amounts Included in the Measurement of Lease Liabilities	$ 23.1	$ 29.9	$ 30.8
Weighted-Average Remaining Lease Term	6 years	6 years	6 years
Weighted-Average Discount Rate	4.32%	4.45%	4.37%

Lessee, Operating Lease, Liabil

Lessee, Operating Lease, Liability, Payment, Due (Details) $ in Millions	Dec. 31, 2022 USD ($)
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 18.2
Lessee, Operating Lease, Liability, Payments, Due Year Two	14.4
Lessee, Operating Lease, Liability, Payments, Due Year Three	11.1
Lessee, Operating Lease, Liability, Payments, Due Year Four	9.1
Lessee, Operating Lease, Liability, Payments, Due Year Five	8.3
Lessee, Operating Lease, Liability, Payments, Due after Year Five	17.4
Lessee, Operating Lease, Liability, Payments, Due	78.5
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	$ 10.6
Operating Lease, Liability	Other Liabilities

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Leases [Abstract]
Operating Lease, Impairment Loss	$ 13.9	$ 12.7
Operating Lease, Right-of-Use-Asset	Other Assets		Other Assets

Statutory Permitted Practice In

Statutory Permitted Practice Information (Detail) - Unum Life Insurance Company of America - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statutory Accounting Practices
Statutory Accounting Practices, Permitted Practice, Cumulative Amount	$ 1,191	$ 667	$ 229
Statutory Accounting Practices, Permitted Practice, Reserve Deficiency	$ 1,660	$ 2,310	$ 2,061

Statutory Financial Informati_3

Statutory Financial Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Traditional U.S. Life Insurance Subsidiaries
Statutory Accounting Practices
Statutory Net Income (Loss)	$ 965.4	$ 779.5	$ 646.8
Statutory Combined Net Gain (Loss) from Operations	965.4	681.1	726.2
Statutory Combined Capital and Surplus	3,816.3	3,950.3
Captive Reinsurers
Statutory Accounting Practices
Statutory Net Income (Loss)	(432.2)	(159)	(201)
Statutory Combined Net Gain (Loss) from Operations	(428.6)	(247.4)	$ (149.4)
Statutory Combined Capital and Surplus	$ 1,229.6	$ 1,258.4

Statutory Financial Informati_4

Statutory Financial Information - Additional Details (Detail) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2022 GBP (£)	Dec. 31, 2021 GBP (£)
Unum Life Insurance Company of America
Statutory Accounting Practices
Statutory Accounting Practices, Permitted Practice, Amount	$ 524	$ 438		$ 229
Fairwind Insurance Company
Statutory Accounting Practices
Statutory Accounting Practices, Permitted Practice, Amount	351	360
Unum Limited
Statutory Accounting Practices
Statutory Net Income | £			£ 121.8
Statutory Combined Capital and Surplus | £						£ 631
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments | £					£ 80
Traditional U.S. Life Insurance Subsidiaries
Statutory Accounting Practices
Statutory Net Income	965.4	779.5		$ 646.8
Statutory Combined Capital and Surplus	3,816.3	3,950.3
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments	991
Cash and Securities Segregated under Federal and Other Regulations	$ 118.8	$ 117.7

Schedule I - Summary of Inves_2

Schedule I - Summary of Investments, Other Than Investments in Related Parties Schedule I - Summary of Investments, Other Than Investments in Related Parties (Details) $ in Millions	Dec. 31, 2022 USD ($)
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	$ 46,452.1	[1]
Amount Shown on the Balance Sheet	43,712.3
Commercial Real Estate
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amount Shown on the Balance Sheet	2,435.4
United States Government and Government Agencies and Authorities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	503.8	[1]
Fair Value of Investments	498.2
Amount Shown on the Balance Sheet	498.2
States, Municipalities, and Political Subdivisions
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	4,006	[1]
Fair Value of Investments	3,457.2
Amount Shown on the Balance Sheet	3,457.2
Foreign Governments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	908.1	[1]
Fair Value of Investments	827.1
Amount Shown on the Balance Sheet	827.1
Public Utilities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	5,170.9	[1]
Fair Value of Investments	4,956.9
Amount Shown on the Balance Sheet	4,956.9
Mortgage/Asset-backed Securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	592.1	[1]
Fair Value of Investments	573.3
Amount Shown on the Balance Sheet	573.3
All Other Corporate Bonds
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	26,640.3	[1]
Fair Value of Investments	24,524.6
Amount Shown on the Balance Sheet	24,524.6
Redeemable Preferred Stocks
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	4	[1]
Fair Value of Investments	3.5
Amount Shown on the Balance Sheet	3.5
Fixed Maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	37,825.2	[1]
Fair Value of Investments	34,840.8
Amount Shown on the Balance Sheet	34,840.8
Policy Loans
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	3,601.2	[1]
Amount Shown on the Balance Sheet	3,601.2
Derivatives
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	0	[1]
Amount Shown on the Balance Sheet	89.1	[2]
Perpetual Preferred Securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	23.1	[1]
Amount Shown on the Balance Sheet	25.8	[3]
Private Equity Partnerships
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	1,032.2
Amount Shown on the Balance Sheet	1,194.3	[3]
Miscellaneous Long-term Investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	130.9	[1]
Amount Shown on the Balance Sheet	130.9	[4]
Short-term Investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost of Investments	1,394.8	[1]
Amount Shown on the Balance Sheet	$ 1,394.8
[1]The amortized cost for fixed maturity securities and mortgage loans represents original cost reduced by repayments, write-downs from declines in fair value, amortization of premiums, and/or accretion of discounts. The amortized cost for these investments does not include allowance for expected credit losses.[2]Derivatives are carried at fair value.[3]The difference between amortized cost and carrying value for private equity partnerships and perpetual preferred equity securities primarily results from changes in the partnership owner's equity and the security's market valuation since acquisition, respectively.[4]The difference between amortized cost and carrying value for private equity partnerships and perpetual preferred equity securities primarily results from changes in the partnership owner's equity and the security's market valuation since acquisition, respectively.

Parent Company Balance Sheet (D

Parent Company Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Balance Sheet Statements, Captions
Amortized Cost of Fixed Maturity Securities	$ 37,825.2	$ 37,386.7
Assets
Fixed Maturity Securities - at fair value (amortized cost: $748.1; $826.4)	34,840.8	43,336
Other Long-term Investments	1,440.1	1,203
Short-term Investments	1,394.8	1,388
Deferred Income Tax Assets, Net	449.8	0
Other Assets	1,786.3	1,825.6
Total Assets	61,434.9	70,115.6
Liabilities
Short-term debt	2	0
Long-term Debt	3,427.8	3,442.2
Other Liabilities	2,334.4	2,585.9
Total Liabilities	52,237.4	58,699.2
Stockholders' Equity
Common Stock	30.8	30.7
Additional Paid-in Capital	2,441	2,408.1
Accumulated Other Comprehensive Income	(2,756.6)	354.1
Retained Earnings	12,912.1	11,853.2
Treasury Stock	(3,429.8)	(3,229.7)
Total Stockholders' Equity	9,197.5	11,416.4	$ 10,871
Total Liabilities and Stockholders' Equity	61,434.9	70,115.6
Parent Company
Condensed Balance Sheet Statements, Captions
Amortized Cost of Fixed Maturity Securities	748.1	826.4
Assets
Fixed Maturity Securities - at fair value (amortized cost: $748.1; $826.4)	657.7	820.8
Other Long-term Investments	19.3	10.3
Short-term Investments	845.8	629.5
Investments in Subsidiaries	11,278.2	13,711.1
Deferred Income Tax Assets, Net	114.9	144.5
Other Assets	555.5	508.1
Total Assets	13,471.4	15,824.3
Liabilities
Short-term debt	2	0
Long-term Debt	3,427.8	3,442.2
Pension and Postretirement Benefits	352.6	507.1
Other Liabilities	491.5	458.6
Total Liabilities	4,273.9	4,407.9
Stockholders' Equity
Common Stock	30.8	30.7
Additional Paid-in Capital	2,441	2,408.1
Accumulated Other Comprehensive Income	(2,756.6)	354.1
Retained Earnings	12,912.1	11,853.2
Treasury Stock	(3,429.8)	(3,229.7)
Total Stockholders' Equity	9,197.5	11,416.4
Total Liabilities and Stockholders' Equity	$ 13,471.4	$ 15,824.3

Parent Company Balance Sheet Ca

Parent Company Balance Sheet Captions (Detail) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Stockholders' Equity
Common Stock, Par Value (in dollars per share)	$ 0.10	$ 0.10
Common Stock, Shares Authorized	725,000,000	725,000,000
Common Stock, Shares Issued	308,306,490	307,334,853
Treasury Stock, Shares at Cost	110,551,977	104,820,670

Parent Company Statement of Inc

Parent Company Statement of Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Income Statements, Captions
Other Income	$ 261.1	$ 242.9	$ 224.2
Total Revenue	11,991	12,013.8	13,162.1
Cost Related to Early Retirement of Debt	4.2	67.3	0
Income Tax Expense (Benefit)	317.2	238.8	171
Net Income	1,314.2	824.2	793
Other Comprehensive Income (Loss), Net of Tax	(3,110.7)	(20.1)	336.9
Comprehensive Income (Loss)	(1,796.5)	804.1	1,129.9
Parent Company
Condensed Income Statements, Captions
Other Income	81.8	53.5	51.7
Total Revenue	1,411.4	1,682.9	1,026.3
Interest and Debt Expense	188.5	185.9	187.1
Cost Related to Early Retirement of Debt	4.2	67.3	0
Other Expenses	35.6	39.1	51.1
Operating Expenses, Total	228.3	292.3	238.2
Income Before Income Tax	1,183.1	1,390.6	788.1
Income Tax Expense (Benefit)	14.7	(24.1)	(15.3)
Income of Parent Company	1,168.4	1,414.7	803.4
Equity in Undistributed Earnings (Loss) of Subsidiaries	145.8	(590.5)	(10.4)
Net Income	1,314.2	824.2	793
Other Comprehensive Income (Loss), Net of Tax	(3,110.7)	(20.1)	336.9
Comprehensive Income (Loss)	(1,796.5)	804.1	1,129.9
Parent Company | Cash Dividend
Condensed Income Statements, Captions
Dividends from Subsidiaries	1,306.6	909.8	974.6
Parent Company | Non-Cash Dividend
Condensed Income Statements, Captions
Dividends from Subsidiaries	$ 23	$ 719.6	$ 0

Parent Company Cash Flow Statem

Parent Company Cash Flow Statement (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Cash Flow Statements, Captions
Cash Provided by Operating Activities	$ 1,418.7	$ 1,387.5	$ 469.3
Cash Flows from Investing Activities
Proceeds from Maturities of Fixed Maturity Securities	1,532.5	2,611.4	2,052.4
Proceeds from Sales and Maturities of Other Investments	445.9	403.1	237
Purchase of Fixed Maturity Securities	(2,835.3)	(4,106.3)	(3,169.6)
Purchase of Other Investments	(482.9)	(606.8)	(440.6)
Net Sales (Purchases) of Short-term Investments	(22.6)	76.5	(133.1)
Net Purchases of Property and Equipment	(102.2)	(110.3)	(119.1)
Cash Used by Investing Activities	(955.9)	(1,340.6)	(267.7)
Cash Flows from Financing Activities
Short-term Debt Repayment	0	0	(400)
Issuance of Long-term Debt	349.2	588.1	494.1
Long-term Debt Repayment	(364)	(500)	(80)
Cost Related to Early Retirement of Debt	3.6	62.8	0
Issuance of Common Stock	4	3.4	4.4
Repurchase of Common Stock	(200.1)	(50)	0
Dividends Paid to Stockholders	(254.2)	(239.4)	(231.9)
Other, Net	(2.9)	4	(1.5)
Cash Used by Financing Activities	(418.6)	(168.9)	(88.7)
Net Increase (Decrease) in Cash and Bank Deposits	44.2	(122)	112.9
Parent Company
Condensed Cash Flow Statements, Captions
Cash Provided by Operating Activities	1,250.2	861	964
Cash Flows from Investing Activities
Proceeds from Maturities of Fixed Maturity Securities	192.1	245.5	138.8
Proceeds from Sales and Maturities of Other Investments	7.4	20.1	46.6
Purchase of Fixed Maturity Securities	(102.7)	(2)	(384.7)
Purchase of Other Investments	(32)	(0.9)	(22)
Net Sales (Purchases) of Short-term Investments	(209.6)	(465)	440.6
Cash Distributions to Subsidiaries	(540.2)	(300.9)	(965.5)
Net Purchases of Property and Equipment	(94)	(91.3)	(81.6)
Cash Used by Investing Activities	(779)	(594.5)	(827.8)
Cash Flows from Financing Activities
Short-term Debt Repayment	0	0	(400)
Issuance of Long-term Debt	349.2	588.1	494.1
Long-term Debt Repayment	(364)	(500)	0
Cost Related to Early Retirement of Debt	3.6	62.8	0
Issuance of Common Stock	4	3.4	4.4
Repurchase of Common Stock	(200.1)	(50)	0
Dividends Paid to Stockholders	(254.2)	(239.4)	(231.9)
Other, Net	0.7	(1.6)	(1.4)
Cash Used by Financing Activities	(468)	(262.3)	(134.8)
Net Increase (Decrease) in Cash and Bank Deposits	$ 3.2	$ 4.2	$ 1.4

Schedule III Supplementary In_2

Schedule III Supplementary Insurance Information (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Supplementary Insurance Information, by Segment
Deferred Acquisition Costs		$ 2,252.3		$ 2,207.9
Reserves for Future Policy Contract Benefits		42,330.2		48,007.5
Unearned Premiums		352.7		347.5
Policy and Contract Benefits		1,839.8		1,907.7
Premium Income		9,623.4		9,481		$ 9,378.1
Net Investment Income	[1]	2,122.2		2,213.2		2,360.7
Benefits and Change in Reserves for Future Benefits		6,936.7	[2]	7,598.6		8,972.9	[2]
Amortization of Deferred Acquisition Costs		591		586.1		606.1
All Other Expenses	[3]	2,831.9		2,766.1		2,619.1
Unum US
Supplementary Insurance Information, by Segment
Deferred Acquisition Costs		1,089.4		1,096.2
Reserves for Future Policy Contract Benefits		9,129.9		10,959.4
Unearned Premiums		50.5		41.5
Policy and Contract Benefits		1,245.8		1,262.5
Premium Income		6,258.3		6,078		6,018.9
Net Investment Income	[1]	676.3		721.6		720.3
Benefits and Change in Reserves for Future Benefits		3,941.5	[2]	4,338.8	[2]	4,138.7
Amortization of Deferred Acquisition Costs		294.9		319		341
All Other Expenses		1,768.8		1,631.9		1,589
Premiums Written	[4]	4,335.7		4,168.9		4,088.6
Unum International
Supplementary Insurance Information, by Segment
Deferred Acquisition Costs		36.6		35.4
Reserves for Future Policy Contract Benefits		2,074.7		2,765.5
Unearned Premiums		130.4		131.8
Policy and Contract Benefits		165.2		171.2
Premium Income		718.8		717		652.8
Net Investment Income	[1]	170.1		132.7		104.6
Benefits and Change in Reserves for Future Benefits		564.8		556.2		500.9
Amortization of Deferred Acquisition Costs		7.6		8		7.4
All Other Expenses		190.4		180.4		173
Premiums Written	[4]	504.1		520.6		456
Colonial Life
Supplementary Insurance Information, by Segment
Deferred Acquisition Costs		1,126.3		1,076.3
Reserves for Future Policy Contract Benefits		2,750.2		2,730.1
Unearned Premiums		35.2		36.3
Policy and Contract Benefits		181.5		210.3
Premium Income		1,702		1,690.2		1,712
Net Investment Income	[1]	152.7		172		155.7
Benefits and Change in Reserves for Future Benefits		803.1		910.4		906.5
Amortization of Deferred Acquisition Costs		288.5		259.1		257.7
All Other Expenses		389.6		364.5		369.2
Premiums Written	[4]	1,221.8		1,223.3		1,252.4
Closed Block
Supplementary Insurance Information, by Segment
Deferred Acquisition Costs		0		0
Reserves for Future Policy Contract Benefits		28,375.4		31,552.5
Unearned Premiums		136.6		137.9
Policy and Contract Benefits		247.3		263.7
Premium Income		944.3		995.8		994.4
Net Investment Income	[1]	1,070.6		1,159		1,370.3
Benefits and Change in Reserves for Future Benefits		1,627.3		1,793.2	[2]	3,426.8	[2]
Amortization of Deferred Acquisition Costs		0		0		0
All Other Expenses		261.5		284		240.2
Premiums Written	[4]	936.8		983		979.3
Corporate and Other Segment
Supplementary Insurance Information, by Segment
Premium Income		0		0		0
Net Investment Income	[1]	52.5		27.9		9.8
Benefits and Change in Reserves for Future Benefits		0		0		0
Amortization of Deferred Acquisition Costs		0		0		0
All Other Expenses		221.6		305.3		247.7
Premiums Written	[4]	$ 0		$ 0		$ 0
[1]Net investment income is allocated based upon segmentation. Each segment has its own specifically identified assets and receives the investment income generated by those assets.[2]Included in benefits and change in reserves for future benefits were the following: • In 2022, a reserve decrease in the Unum US segment related to reserve assumption updates in our Unum US group long-term disability and group life product lines, of $121.0 million and $34.0 million, respectively. • In 2021, a reserve decrease of $215.0 million in the Unum US segment related to reserve assumption updates in our Unum US group long-term disability product line. Also in 2021, reserve increases in the Closed Block segment related to reserve assumption updates for our long-term care, group pension, and individual disability product lines, of $2.1 million, $25.1 million, and $6.4 million, respectively. • In 2020, reserve increases in the Closed Block segment related to reserve assumption updates for our long-term care and group pension product lines of $151.5 million and $17.5 million, respectively. • In 2021 and 2020, an increase in benefits and change in reserves for future benefits of $133.1 million and $1,284.5 million, respectively, resulting from the recognition of the adjustment related to unrealized investment gains and losses previously recognized in accumulated other comprehensive income related to the Closed Block individual disability reinsurance transaction. • In 2022, 2021, and 2020 the amortization of the cost of reinsurance of $63.8 million, $79.1 million, and $2.6 million respectively, in the Closed Block segment. • In 2021, an impairment loss of $12.1 million was recorded in our Corporate segment for previously capitalized internal-use software that we no longer plan to utilize. • In 2021, costs related to early retirement of debt of $67.3 million in the Corporate segment. • In 2021 and 2020, transaction costs of $6.2 million and $21.0 million, respectively, related to the Closed Block individual disability reinsurance transaction. • In 2021 and 2020, a right-of-use asset impairment of $13.9 million and $12.7 million, respectively, related to one of our operating leases for office space that we do not plan to continue using to support general operations in the Corporate segment. • In 2020, costs related to organizational design updates of $23.3 million in the Corporate segment.

Schedule IV Reinsurance (Detail

Schedule IV Reinsurance (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reinsurance Premiums for Insurance Companies, by Product Segment
Direct Premiums, Life Insurance in Force	$ 1,057,312.2	$ 1,007,562.2	$ 979,755.7
Ceded Premiums, Life Insurance in Force	35,773.9	37,794.6	41,550.9
Assumed Premiums, Life Insurance in Force	931.9	920.3	896.4
Premiums, Net, Life Insurance in Force	$ 1,022,470.2	$ 970,687.9	$ 939,101.2
Life Insurance in Force Premiums, Percentage Assumed to Net	0.10%	0.10%	0.10%
Gross Amount	$ 9,900.5	$ 9,742.8	$ 9,621.9
Reinsurance Ceded	355.8	352.4	337.9
Assumed Premiums Earned	78.7	90.6	94.1
Net Amount	$ 9,623.4	$ 9,481	$ 9,378.1
Percentage of Amount Assumed to Net	0.80%	1%	1%
Life Insurance
Reinsurance Premiums for Insurance Companies, by Product Segment
Gross Amount	$ 2,711.2	$ 2,550.7	$ 2,536.8
Reinsurance Ceded	155.1	150.2	141.9
Assumed Premiums Earned	6.5	7.6	8
Net Amount	$ 2,562.6	$ 2,408.1	$ 2,402.9
Percentage of Amount Assumed to Net	0.30%	0.30%	0.30%
Accident, Health, and Other Insurance
Reinsurance Premiums for Insurance Companies, by Product Segment
Gross Amount	$ 7,189.3	$ 7,192.1	$ 7,085.1
Reinsurance Ceded	200.7	202.2	196
Assumed Premiums Earned	72.2	83	86.1
Net Amount	$ 7,060.8	$ 7,072.9	$ 6,975.2
Percentage of Amount Assumed to Net	1%	1.20%	1.20%

Schedule V Valuation and Qual_2

Schedule V Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Allowance for expected credit losses (deducted from accounts and premiums receivable)
Valuation and Qualifying Accounts Disclosure
Balance at Beginning of Year		$ 34.2	$ 38.8
Additions Charged to Costs and Expenses		10.8	18.2	$ 34.2
Additions Charged to Other Accounts	[1]	0	0	0.1
Deductions	[2]	12.5	22.8	19.3
Balance at End of Year		32.5	34.2	38.8
Allowance for expected credit losses (deducted from accounts and premiums receivable) | Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjusted Balance
Valuation and Qualifying Accounts Disclosure
Balance at Beginning of Year	[3]			23.8
Allowance for expected credit losses (deducted from reinsurance recoverable)
Valuation and Qualifying Accounts Disclosure
Balance at Beginning of Year		2.3	11.7
Additions Charged to Costs and Expenses		0	0.7	10.1
Additions Charged to Other Accounts	[1]	0	0	0
Deductions	[2]	0.6	10.1	0.2
Balance at End of Year		$ 1.7	2.3	11.7
Allowance for expected credit losses (deducted from reinsurance recoverable) | Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjusted Balance
Valuation and Qualifying Accounts Disclosure
Balance at Beginning of Year	[3]			1.8
Real Estate reserve (deducted from other long-term investments)
Valuation and Qualifying Accounts Disclosure
Balance at Beginning of Year			$ 0	0.3
Additions Charged to Costs and Expenses				0
Additions Charged to Other Accounts	[1]			0
Deductions	[2]			0.3
Balance at End of Year				$ 0
[1]Additions charged to other accounts are comprised of amounts related to fluctuations in the foreign currency exchange rate.[2]Deductions include amounts deemed to reduce exposure of expected losses on premium and accounts receivables and reinsurance recoverable, probable losses on Real Estate reserve, amounts deemed uncollectible, and amounts related to fluctuations in the foreign currency exchange rate.[3]In 2020, ASC 326 "Financial Instruments - Credit Losses" was adopted resulting in a beginning balance adjustment of $13.5 million to increase the Allowance for expected credit losses (deducted from accounts and premiums receivable) and a $1.8 million beginning balance adjustment to increase the Allowance for expected credit losses (deducted from reinsurance recoverable).